[FFmpeg-devel] [PATCH v3 0/5] Add support for Closed Caption FIFO

[FFmpeg-devel] [PATCH v3 0/5] Add support for Closed Caption FIFO

[Devin Heitmueller]

This updated patch series addresses all issues reported to date.
Specifically, the latest round includes a memory leak spotted by
Lance Wang and the functions have been renamed to be prefixed with ff_
per James Almer's suggestion.

Thanks,

Devin

Devin Heitmueller (5):
  ccfifo: Properly handle CEA-708 captions through framerate conversion
  vf_fps: properly preserve CEA-708 captions
  yadif: Properly preserve CEA-708 closed captions
  tinterlace: Properly preserve CEA-708 closed captions
  vf_ccrepack: Add new filter to repack CEA-708 side data

 doc/filters.texi            |  10 +++
 libavfilter/Makefile        |   2 +
 libavfilter/allfilters.c    |   1 +
 libavfilter/ccfifo.c        | 191 ++++++++++++++++++++++++++++++++++++++++++++
 libavfilter/ccfifo.h        |  85 ++++++++++++++++++++
 libavfilter/tinterlace.h    |   2 +
 libavfilter/vf_bwdif.c      |   7 ++
 libavfilter/vf_ccrepack.c   | 100 +++++++++++++++++++++++
 libavfilter/vf_fps.c        |   9 ++-
 libavfilter/vf_tinterlace.c |   9 +++
 libavfilter/vf_yadif.c      |   6 ++
 libavfilter/vf_yadif_cuda.c |   8 ++
 libavfilter/yadif.h         |   2 +
 libavfilter/yadif_common.c  |   5 ++
 14 files changed, 436 insertions(+), 1 deletion(-)
 create mode 100644 libavfilter/ccfifo.c
 create mode 100644 libavfilter/ccfifo.h
 create mode 100644 libavfilter/vf_ccrepack.c

-- 
1.8.3.1

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[FFmpeg-devel] [PATCH v3 1/5] ccfifo: Properly handle CEA-708 captions through framerate conversion

[Devin Heitmueller]

When transcoding video that contains 708 closed captions, the
caption data is tied to the frames as side data.  Simply dropping
or adding frames to change the framerate will result in loss of
data, so the caption data needs to be preserved and reformatted.

For example, without this patch converting 720p59 to 1080i59
would result in loss of 50% of the caption bytes, resulting in
garbled 608 captions and 708 probably wouldn't render at all.
Further, the frames that are there will have an illegal
cc_count for the target framerate, so some decoders may ignore
the packets entirely.

Extract the 608 and 708 tuples and insert them onto queues.  Then
after dropping/adding frames, re-write the tuples back into the
resulting frames at the appropriate rate given the target
framerate.  This includes both having the correct cc_count as
well as clocking out the 608 pairs at the appropriate rate.

Signed-off-by: Devin Heitmueller <dheitmueller@ltnglobal.com>
---
 libavfilter/Makefile |   1 +
 libavfilter/ccfifo.c | 191 +++++++++++++++++++++++++++++++++++++++++++++++++++
 libavfilter/ccfifo.h |  85 +++++++++++++++++++++++
 3 files changed, 277 insertions(+)
 create mode 100644 libavfilter/ccfifo.c
 create mode 100644 libavfilter/ccfifo.h

diff --git a/libavfilter/Makefile b/libavfilter/Makefile
index 71e198b..628ade8 100644
--- a/libavfilter/Makefile
+++ b/libavfilter/Makefile
@@ -14,6 +14,7 @@ OBJS = allfilters.o                                                     \
        buffersink.o                                                     \
        buffersrc.o                                                      \
        colorspace.o                                                     \
+       ccfifo.o                                                         \
        drawutils.o                                                      \
        fifo.o                                                           \
        formats.o                                                        \
diff --git a/libavfilter/ccfifo.c b/libavfilter/ccfifo.c
new file mode 100644
index 0000000..3f8be57
--- /dev/null
+++ b/libavfilter/ccfifo.c
@@ -0,0 +1,191 @@
+/*
+ * CEA-708 Closed Captioning FIFO
+ * Copyright (c) 2023 LTN Global Communications
+ *
+ * Author: Devin Heitmueller <dheitmueller@ltnglobal.com>
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include "ccfifo.h"
+
+struct AVCCFifo {
+    AVFifo *cc_608_fifo;
+    AVFifo *cc_708_fifo;
+    int expected_cc_count;
+    int expected_608;
+    int cc_detected;
+    void *log_ctx;
+};
+
+#define MAX_CC_ELEMENTS 128
+#define CC_BYTES_PER_ENTRY 3
+
+struct cc_lookup {
+    int num;
+    int den;
+    int cc_count;
+    int num_608;
+};
+
+const static struct cc_lookup cc_lookup_vals[] = {
+    { 15, 1, 40, 4 },
+    { 24, 1, 25, 3 },
+    { 24000, 1001, 25, 3 },
+    { 30, 1, 20, 2 },
+    { 30000, 1001, 20, 2},
+    { 60, 1, 10, 1 },
+    { 60000, 1001, 10, 1},
+};
+
+void ff_ccfifo_freep(AVCCFifo **ccf)
+{
+    if (ccf && *ccf) {
+        AVCCFifo *tmp = *ccf;
+        if (tmp->cc_608_fifo)
+            av_fifo_freep2(&tmp->cc_608_fifo);
+        if (tmp->cc_708_fifo)
+            av_fifo_freep2(&tmp->cc_708_fifo);
+        av_freep(*ccf);
+    }
+}
+
+AVCCFifo *ff_ccfifo_alloc(AVRational *framerate, void *log_ctx)
+{
+    AVCCFifo *ccf;
+    int i;
+
+    ccf = av_mallocz(sizeof(*ccf));
+    if (!ccf)
+        return NULL;
+
+    if (!(ccf->cc_708_fifo = av_fifo_alloc2(MAX_CC_ELEMENTS, CC_BYTES_PER_ENTRY, 0)))
+        goto error;
+
+    if (!(ccf->cc_608_fifo = av_fifo_alloc2(MAX_CC_ELEMENTS, CC_BYTES_PER_ENTRY, 0)))
+        goto error;
+
+    /* Based on the target FPS, figure out the expected cc_count and number of
+       608 tuples per packet.  See ANSI/CTA-708-E Sec 4.3.6.1. */
+    for (i = 0; i < (sizeof(cc_lookup_vals) / sizeof(struct cc_lookup)); i++) {
+        if (framerate->num == cc_lookup_vals[i].num &&
+            framerate->den == cc_lookup_vals[i].den) {
+            ccf->expected_cc_count = cc_lookup_vals[i].cc_count;
+            ccf->expected_608 = cc_lookup_vals[i].num_608;
+            break;
+        }
+    }
+
+    if (ccf->expected_608 == 0) {
+        av_log(ccf->log_ctx, AV_LOG_WARNING, "cc_fifo cannot transcode captions fps=%d/%d\n",
+               framerate->num, framerate->den);
+        return NULL;
+    }
+
+    return ccf;
+
+error:
+    ff_ccfifo_freep(&ccf);
+    return NULL;
+}
+
+int ff_ccfifo_inject(AVCCFifo *ccf, AVFrame *frame)
+{
+    AVFrameSideData *sd;
+    int cc_filled = 0;
+    int i;
+
+    if (!ccf)
+        return 0;
+
+    if (ccf->cc_detected == 0 || ccf->expected_cc_count == 0)
+        return 0;
+
+    sd = av_frame_new_side_data(frame, AV_FRAME_DATA_A53_CC,
+                                ccf->expected_cc_count * CC_BYTES_PER_ENTRY);
+    if (!sd)
+        return 0;
+
+    for (i = 0; i < ccf->expected_608; i++) {
+        if (av_fifo_can_read(ccf->cc_608_fifo) >= CC_BYTES_PER_ENTRY) {
+            av_fifo_read(ccf->cc_608_fifo, &sd->data[cc_filled * CC_BYTES_PER_ENTRY],
+                         CC_BYTES_PER_ENTRY);
+            cc_filled++;
+        } else {
+            break;
+        }
+    }
+
+    /* Insert any available data from the 708 FIFO */
+    while (cc_filled < ccf->expected_cc_count) {
+        if (av_fifo_can_read(ccf->cc_708_fifo) >= CC_BYTES_PER_ENTRY) {
+            av_fifo_read(ccf->cc_708_fifo, &sd->data[cc_filled * CC_BYTES_PER_ENTRY],
+                         CC_BYTES_PER_ENTRY);
+            cc_filled++;
+        } else {
+            break;
+        }
+    }
+
+    /* Insert 708 padding into any remaining fields */
+    while (cc_filled < ccf->expected_cc_count) {
+        sd->data[cc_filled * CC_BYTES_PER_ENTRY]     = 0xfa;
+        sd->data[cc_filled * CC_BYTES_PER_ENTRY + 1] = 0x00;
+        sd->data[cc_filled * CC_BYTES_PER_ENTRY + 2] = 0x00;
+        cc_filled++;
+    }
+
+    return 0;
+}
+
+int ff_ccfifo_extract(AVCCFifo *ccf, AVFrame *frame)
+{
+    int i;
+
+    if (!ccf)
+        return 0;
+
+    /* Read the A53 side data, discard padding, and put 608/708 into
+       queues so we can ensure they get into the output frames at
+       the correct rate... */
+    if (ccf->expected_cc_count > 0) {
+        AVFrameSideData *side_data = av_frame_get_side_data(frame, AV_FRAME_DATA_A53_CC);
+        if (side_data) {
+            uint8_t *cc_bytes = side_data->data;
+            int cc_count = side_data->size / CC_BYTES_PER_ENTRY;
+            ccf->cc_detected = 1;
+
+            for (i = 0; i < cc_count; i++) {
+                /* See ANSI/CTA-708-E Sec 4.3, Table 3 */
+                uint8_t cc_valid = (cc_bytes[CC_BYTES_PER_ENTRY*i] & 0x04) >> 2;
+                uint8_t cc_type = cc_bytes[CC_BYTES_PER_ENTRY*i] & 0x03;
+                if (cc_type == 0x00 || cc_type == 0x01) {
+                    av_fifo_write(ccf->cc_608_fifo, &cc_bytes[CC_BYTES_PER_ENTRY*i],
+                                  CC_BYTES_PER_ENTRY);
+                } else if (cc_valid && (cc_type == 0x02 || cc_type == 0x03)) {
+                    av_fifo_write(ccf->cc_708_fifo, &cc_bytes[CC_BYTES_PER_ENTRY*i],
+                                  CC_BYTES_PER_ENTRY);
+                }
+            }
+
+            /* Remove the side data, as we will re-create it on the
+               output as needed */
+            av_frame_remove_side_data(frame, AV_FRAME_DATA_A53_CC);
+        }
+    }
+    return 0;
+}
diff --git a/libavfilter/ccfifo.h b/libavfilter/ccfifo.h
new file mode 100644
index 0000000..70e8b9b
--- /dev/null
+++ b/libavfilter/ccfifo.h
@@ -0,0 +1,85 @@
+/*
+ * CEA-708 Closed Captioning FIFO
+ * Copyright (c) 2023 LTN Global Communications
+ *
+ * Author: Devin Heitmueller <dheitmueller@ltnglobal.com>
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+/**
+ * @file
+ * CC FIFO Buffer
+ */
+
+#ifndef AVUTIL_CCFIFO_H
+#define AVUTIL_CCFIFO_H
+
+#include "libavutil/avutil.h"
+#include "libavutil/frame.h"
+#include "libavutil/fifo.h"
+
+typedef struct AVCCFifo AVCCFifo;
+
+/**
+ * Allocate an AVCCFifo.
+ *
+ * @param sample_fmt  sample format
+ * @param channels    number of channels
+ * @param nb_samples  initial allocation size, in samples
+ * @return            newly allocated AVCCFifo, or NULL on error
+ */
+AVCCFifo *ff_ccfifo_alloc(AVRational *framerate, void *log_ctx);
+
+/**
+ * Free an AVCCFifo
+ *
+ * @param ccf Pointer to the pointer to the AVCCFifo which should be freed
+ * @note `*ptr = NULL` is safe and leads to no action.
+ */
+void ff_ccfifo_freep(AVCCFifo **ccf);
+
+
+/**
+ * Read a frame into a CC Fifo
+ *
+ * Extract CC bytes from the AVFrame, insert them into our queue, and
+ * remove the side data from the AVFrame.  The side data is removed
+ * as it will be re-inserted at the appropriate rate later in the
+ * filter.
+ *
+ * @param af          AVCCFifo to write to
+ * @param frame       AVFrame with the video frame to operate on
+ * @return            Zero on success, or negative AVERROR
+ *                    code on failure.
+ */
+int ff_ccfifo_extract(AVCCFifo *af, AVFrame *frame);
+
+/**
+ * Insert CC data from the FIFO into an AVFrame (as side data)
+ *
+ * Dequeue the appropriate number of CC tuples based on the
+ * frame rate, and insert them into the AVFrame
+ *
+ * @param af          AVCCFifo to read from
+ * @param frame       AVFrame with the video frame to operate on
+ * @return            Zero on success, or negative AVERROR
+ *                    code on failure.
+ */
+int ff_ccfifo_inject(AVCCFifo *af, AVFrame *frame);
+
+#endif /* AVUTIL_CCFIFO_H */
-- 
1.8.3.1

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[FFmpeg-devel] [PATCH v3 2/5] vf_fps: properly preserve CEA-708 captions

[Devin Heitmueller]

The existing implementation made an attempt to remove duplicate
captions if increasing the framerate, but made no attempt to
handle reducing the framerate, nor did it rewrite the caption
payloads to have the appropriate cc_count (e.g. the cc_count needs
to change from 20 to 10 when going from 1080i59 to 720p59 and
vice-versa).

Make use of the new ccfifo mechanism to ensure that caption data
is properly preserved.

Signed-off-by: Devin Heitmueller <dheitmueller@ltnglobal.com>
---
 libavfilter/vf_fps.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/libavfilter/vf_fps.c b/libavfilter/vf_fps.c
index 051d278..06e7441 100644
--- a/libavfilter/vf_fps.c
+++ b/libavfilter/vf_fps.c
@@ -34,6 +34,7 @@
 #include "libavutil/mathematics.h"
 #include "libavutil/opt.h"
 #include "avfilter.h"
+#include "ccfifo.h"
 #include "filters.h"
 #include "internal.h"
 
@@ -85,6 +86,7 @@ typedef struct FPSContext {
 
     AVFrame *frames[2];     ///< buffered frames
     int      frames_count;  ///< number of buffered frames
+    AVCCFifo *cc_fifo;      ///< closed captions
 
     int64_t  next_pts;      ///< pts of the next frame to output
 
@@ -165,6 +167,7 @@ static av_cold void uninit(AVFilterContext *ctx)
         frame = shift_frame(ctx, s);
         av_frame_free(&frame);
     }
+    ff_ccfifo_freep(&s->cc_fifo);
 
     av_log(ctx, AV_LOG_VERBOSE, "%d frames in, %d frames out; %d frames dropped, "
            "%d frames duplicated.\n", s->frames_in, s->frames_out, s->drop, s->dup);
@@ -210,6 +213,9 @@ static int config_props(AVFilterLink* outlink)
                s->in_pts_off, s->out_pts_off, s->start_time);
     }
 
+    if (!(s->cc_fifo = ff_ccfifo_alloc(&outlink->frame_rate, ctx)))
+        av_log(ctx, AV_LOG_VERBOSE, "Failure to setup CC FIFO queue.  Captions will be passed through\n");
+
     av_log(ctx, AV_LOG_VERBOSE, "fps=%d/%d\n", outlink->frame_rate.num, outlink->frame_rate.den);
 
     return 0;
@@ -242,6 +248,7 @@ static int read_frame(AVFilterContext *ctx, FPSContext *s, AVFilterLink *inlink,
     av_log(ctx, AV_LOG_DEBUG, "Read frame with in pts %"PRId64", out pts %"PRId64"\n",
            in_pts, frame->pts);
 
+    ff_ccfifo_extract(s->cc_fifo, frame);
     s->frames[s->frames_count++] = frame;
     s->frames_in++;
 
@@ -289,7 +296,7 @@ static int write_frame(AVFilterContext *ctx, FPSContext *s, AVFilterLink *outlin
         if (!frame)
             return AVERROR(ENOMEM);
         // Make sure Closed Captions will not be duplicated
-        av_frame_remove_side_data(s->frames[0], AV_FRAME_DATA_A53_CC);
+        ff_ccfifo_inject(s->cc_fifo, frame);
         frame->pts = s->next_pts++;
         frame->duration = 1;
 
-- 
1.8.3.1

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[FFmpeg-devel] [PATCH v3 3/5] yadif: Properly preserve CEA-708 closed captions

[Devin Heitmueller]

Various deinterlacing modes have the effect of doubling the
framerate, and we need to ensure that the caption data isn't
duplicated (or else you get double captions on-screen).

Use the new ccfifo mechanism for yadif (and yadif_cuda and bwdif
since they use the same yadif core) so that CEA-708 data is
properly preserved through this filter.

Signed-off-by: Devin Heitmueller <dheitmueller@ltnglobal.com>
---
 libavfilter/vf_bwdif.c      | 7 +++++++
 libavfilter/vf_yadif.c      | 6 ++++++
 libavfilter/vf_yadif_cuda.c | 8 ++++++++
 libavfilter/yadif.h         | 2 ++
 libavfilter/yadif_common.c  | 5 +++++
 5 files changed, 28 insertions(+)

diff --git a/libavfilter/vf_bwdif.c b/libavfilter/vf_bwdif.c
index 34e8c5e..a97a468 100644
--- a/libavfilter/vf_bwdif.c
+++ b/libavfilter/vf_bwdif.c
@@ -297,6 +297,7 @@ static av_cold void uninit(AVFilterContext *ctx)
     av_frame_free(&yadif->prev);
     av_frame_free(&yadif->cur );
     av_frame_free(&yadif->next);
+    ff_ccfifo_freep(&yadif->cc_fifo);
 }
 
 static const enum AVPixelFormat pix_fmts[] = {
@@ -332,6 +333,12 @@ static int config_props(AVFilterLink *link)
 
     if(yadif->mode&1)
         link->frame_rate = av_mul_q(link->src->inputs[0]->frame_rate, (AVRational){2,1});
+    else
+        link->frame_rate = ctx->inputs[0]->frame_rate;
+
+    if (!(yadif->cc_fifo = ff_ccfifo_alloc(&link->frame_rate, ctx)))
+        av_log(ctx, AV_LOG_VERBOSE, "Failure to setup CC FIFO queue.  Captions will be passed through\n");
+
 
     if (link->w < 3 || link->h < 4) {
         av_log(ctx, AV_LOG_ERROR, "Video of less than 3 columns or 4 lines is not supported\n");
diff --git a/libavfilter/vf_yadif.c b/libavfilter/vf_yadif.c
index 1be02de..36ecc0d 100644
--- a/libavfilter/vf_yadif.c
+++ b/libavfilter/vf_yadif.c
@@ -261,6 +261,7 @@ static av_cold void uninit(AVFilterContext *ctx)
     av_frame_free(&yadif->prev);
     av_frame_free(&yadif->cur );
     av_frame_free(&yadif->next);
+    ff_ccfifo_freep(&yadif->cc_fifo);
 }
 
 static const enum AVPixelFormat pix_fmts[] = {
@@ -293,6 +294,11 @@ static int config_output(AVFilterLink *outlink)
     if(s->mode & 1)
         outlink->frame_rate = av_mul_q(ctx->inputs[0]->frame_rate,
                                     (AVRational){2, 1});
+    else
+        outlink->frame_rate = ctx->inputs[0]->frame_rate;
+
+    if (!(s->cc_fifo = ff_ccfifo_alloc(&outlink->frame_rate, ctx)))
+        av_log(ctx, AV_LOG_VERBOSE, "Failure to setup CC FIFO queue.  Captions will be passed through\n");
 
     if (outlink->w < 3 || outlink->h < 3) {
         av_log(ctx, AV_LOG_ERROR, "Video of less than 3 columns or lines is not supported\n");
diff --git a/libavfilter/vf_yadif_cuda.c b/libavfilter/vf_yadif_cuda.c
index 685b8a2..c6cbdca 100644
--- a/libavfilter/vf_yadif_cuda.c
+++ b/libavfilter/vf_yadif_cuda.c
@@ -206,6 +206,9 @@ static av_cold void deint_cuda_uninit(AVFilterContext *ctx)
     av_frame_free(&y->cur);
     av_frame_free(&y->next);
 
+    if (yadif->cc_fifo)
+        ff_cc_fifo_free(yadif->cc_fifo);
+
     av_buffer_unref(&s->device_ref);
     s->hwctx = NULL;
     av_buffer_unref(&s->input_frames_ref);
@@ -291,6 +294,11 @@ static int config_output(AVFilterLink *link)
     if(y->mode & 1)
         link->frame_rate = av_mul_q(ctx->inputs[0]->frame_rate,
                                     (AVRational){2, 1});
+    else
+        outlink->frame_rate = ctx->inputs[0]->frame_rate;
+
+    if (!(s->cc_fifo = ff_cc_fifo_alloc(&outlink->frame_rate, ctx)))
+        av_log(ctx, AV_LOG_VERBOSE, "Failure to setup CC FIFO queue.  Captions will be passed through\n");
 
     if (link->w < 3 || link->h < 3) {
         av_log(ctx, AV_LOG_ERROR, "Video of less than 3 columns or lines is not supported\n");
diff --git a/libavfilter/yadif.h b/libavfilter/yadif.h
index c928911..1077576 100644
--- a/libavfilter/yadif.h
+++ b/libavfilter/yadif.h
@@ -22,6 +22,7 @@
 #include "libavutil/opt.h"
 #include "libavutil/pixdesc.h"
 #include "avfilter.h"
+#include "ccfifo.h"
 
 enum YADIFMode {
     YADIF_MODE_SEND_FRAME           = 0, ///< send 1 frame for each frame
@@ -76,6 +77,7 @@ typedef struct YADIFContext {
     int eof;
     uint8_t *temp_line;
     int temp_line_size;
+    AVCCFifo *cc_fifo;
 
     /*
      * An algorithm that treats first and/or last fields in a sequence
diff --git a/libavfilter/yadif_common.c b/libavfilter/yadif_common.c
index a10cf7a..676853e 100644
--- a/libavfilter/yadif_common.c
+++ b/libavfilter/yadif_common.c
@@ -60,6 +60,8 @@ static int return_frame(AVFilterContext *ctx, int is_second)
             yadif->out->pts = AV_NOPTS_VALUE;
         }
     }
+
+    ff_ccfifo_inject(yadif->cc_fifo, yadif->out);
     ret = ff_filter_frame(ctx->outputs[0], yadif->out);
 
     yadif->frame_pending = (yadif->mode&1) && !is_second;
@@ -96,6 +98,8 @@ int ff_yadif_filter_frame(AVFilterLink *link, AVFrame *frame)
 
     av_assert0(frame);
 
+    ff_ccfifo_extract(yadif->cc_fifo, frame);
+
     if (yadif->frame_pending)
         return_frame(ctx, 1);
 
@@ -137,6 +141,7 @@ int ff_yadif_filter_frame(AVFilterLink *link, AVFrame *frame)
         if (!yadif->out)
             return AVERROR(ENOMEM);
 
+        ff_ccfifo_inject(yadif->cc_fifo, yadif->out);
         av_frame_free(&yadif->prev);
         if (yadif->out->pts != AV_NOPTS_VALUE)
             yadif->out->pts *= 2;
-- 
1.8.3.1

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[FFmpeg-devel] [PATCH v3 4/5] tinterlace: Properly preserve CEA-708 closed captions

[Devin Heitmueller]

Because the interlacing filter halves the effective framerate, we
need to ensure that no CEA-708 data is lost as frames are merged.

Make use of the new ccfifo mechanism to ensure that caption data
is properly preserved as frames pass through the filter.

Thanks to Thomas Mundt for review and noticing a couple of
missed codepaths for injection on output.  Thanks to Lance Wang
for pointing out a memory leak.

Signed-off-by: Devin Heitmueller <dheitmueller@ltnglobal.com>
---
 libavfilter/tinterlace.h    | 2 ++
 libavfilter/vf_tinterlace.c | 9 +++++++++
 2 files changed, 11 insertions(+)

diff --git a/libavfilter/tinterlace.h b/libavfilter/tinterlace.h
index 37b6c10..9f5ce7e 100644
--- a/libavfilter/tinterlace.h
+++ b/libavfilter/tinterlace.h
@@ -32,6 +32,7 @@
 #include "libavutil/pixdesc.h"
 #include "drawutils.h"
 #include "avfilter.h"
+#include "ccfifo.h"
 
 #define TINTERLACE_FLAG_VLPF 01
 #define TINTERLACE_FLAG_CVLPF 2
@@ -77,6 +78,7 @@ typedef struct TInterlaceContext {
     const AVPixFmtDescriptor *csp;
     void (*lowpass_line)(uint8_t *dstp, ptrdiff_t width, const uint8_t *srcp,
                          ptrdiff_t mref, ptrdiff_t pref, int clip_max);
+    AVCCFifo *cc_fifo;
 } TInterlaceContext;
 
 void ff_tinterlace_init_x86(TInterlaceContext *interlace);
diff --git a/libavfilter/vf_tinterlace.c b/libavfilter/vf_tinterlace.c
index 0326292..090c7a7 100644
--- a/libavfilter/vf_tinterlace.c
+++ b/libavfilter/vf_tinterlace.c
@@ -203,6 +203,7 @@ static av_cold void uninit(AVFilterContext *ctx)
     av_frame_free(&tinterlace->next);
     av_freep(&tinterlace->black_data[0][0]);
     av_freep(&tinterlace->black_data[1][0]);
+    ff_ccfifo_freep(&tinterlace->cc_fifo);
 }
 
 static int config_out_props(AVFilterLink *outlink)
@@ -291,6 +292,9 @@ static int config_out_props(AVFilterLink *outlink)
 #endif
     }
 
+    if (!(tinterlace->cc_fifo = ff_ccfifo_alloc(&outlink->frame_rate, ctx)))
+        av_log(ctx, AV_LOG_VERBOSE, "Failure to setup CC FIFO queue.  Captions will be passed through\n");
+
     av_log(ctx, AV_LOG_VERBOSE, "mode:%d filter:%s h:%d -> h:%d\n", tinterlace->mode,
            (tinterlace->flags & TINTERLACE_FLAG_CVLPF) ? "complex" :
            (tinterlace->flags & TINTERLACE_FLAG_VLPF) ? "linear" : "off",
@@ -375,6 +379,8 @@ static int filter_frame(AVFilterLink *inlink, AVFrame *picref)
     tinterlace->cur  = tinterlace->next;
     tinterlace->next = picref;
 
+    ff_ccfifo_extract(tinterlace->cc_fifo, picref);
+
     cur = tinterlace->cur;
     next = tinterlace->next;
     /* we need at least two frames */
@@ -451,6 +457,7 @@ static int filter_frame(AVFilterLink *inlink, AVFrame *picref)
             if (!out)
                 return AVERROR(ENOMEM);
             out->pts /= 2;  // adjust pts to new framerate
+            ff_ccfifo_inject(tinterlace->cc_fifo, out);
             ret = ff_filter_frame(outlink, out);
             return ret;
         }
@@ -486,6 +493,7 @@ static int filter_frame(AVFilterLink *inlink, AVFrame *picref)
             out->pts = cur->pts*2;
 
         out->pts = av_rescale_q(out->pts, tinterlace->preout_time_base, outlink->time_base);
+        ff_ccfifo_inject(tinterlace->cc_fifo, out);
         if ((ret = ff_filter_frame(outlink, out)) < 0)
             return ret;
 
@@ -521,6 +529,7 @@ static int filter_frame(AVFilterLink *inlink, AVFrame *picref)
 
     out->pts = av_rescale_q(out->pts, tinterlace->preout_time_base, outlink->time_base);
     out->duration = av_rescale_q(1, av_inv_q(outlink->frame_rate), outlink->time_base);
+    ff_ccfifo_inject(tinterlace->cc_fifo, out);
     ret = ff_filter_frame(outlink, out);
 
     return ret;
-- 
1.8.3.1

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[FFmpeg-devel] [PATCH v3 5/5] vf_ccrepack: Add new filter to repack CEA-708 side data

[Devin Heitmueller]

THis filter can correct certain issues seen from upstream sources
where the cc_count is not properly set or the CEA-608 tuples are
not at the start of the payload as expected.

Make use of the ccfifo to extract and immediately repack the CEA-708
side data, thereby removing any extra padding and ensuring the 608
tuples are at the front of the payload.

Signed-off-by: Devin Heitmueller <dheitmueller@ltnglobal.com>
---
 doc/filters.texi          |  10 +++++
 libavfilter/Makefile      |   1 +
 libavfilter/allfilters.c  |   1 +
 libavfilter/vf_ccrepack.c | 100 ++++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 112 insertions(+)
 create mode 100644 libavfilter/vf_ccrepack.c

diff --git a/doc/filters.texi b/doc/filters.texi
index 120fe66..e72e73d 100644
--- a/doc/filters.texi
+++ b/doc/filters.texi
@@ -8930,6 +8930,16 @@ Only deinterlace frames marked as interlaced.
 The default value is @code{all}.
 @end table
 
+@section ccrepack
+
+Repack CEA-708 closed captioning side data
+
+This filter fixes various issues seen with commerical encoders
+related to upstream malformed CEA-708 payloads, specifically
+incorrect number of tuples (wrong cc_count for the target FPS),
+and incorrect ordering of tuples (i.e. the CEA-608 tuples are not at
+the first entries in the payload).
+
 @section cas
 
 Apply Contrast Adaptive Sharpen filter to video stream.
diff --git a/libavfilter/Makefile b/libavfilter/Makefile
index 628ade8..3d0b3ad 100644
--- a/libavfilter/Makefile
+++ b/libavfilter/Makefile
@@ -212,6 +212,7 @@ OBJS-$(CONFIG_BOXBLUR_OPENCL_FILTER)         += vf_avgblur_opencl.o opencl.o \
                                                 opencl/avgblur.o boxblur.o
 OBJS-$(CONFIG_BWDIF_FILTER)                  += vf_bwdif.o yadif_common.o
 OBJS-$(CONFIG_CAS_FILTER)                    += vf_cas.o
+OBJS-$(CONFIG_CCREPACK_FILTER)               += vf_ccrepack.o
 OBJS-$(CONFIG_CHROMABER_VULKAN_FILTER)       += vf_chromaber_vulkan.o vulkan.o vulkan_filter.o
 OBJS-$(CONFIG_CHROMAHOLD_FILTER)             += vf_chromakey.o
 OBJS-$(CONFIG_CHROMAKEY_FILTER)              += vf_chromakey.o
diff --git a/libavfilter/allfilters.c b/libavfilter/allfilters.c
index d7db46c..b38550b 100644
--- a/libavfilter/allfilters.c
+++ b/libavfilter/allfilters.c
@@ -196,6 +196,7 @@ extern const AVFilter ff_vf_boxblur;
 extern const AVFilter ff_vf_boxblur_opencl;
 extern const AVFilter ff_vf_bwdif;
 extern const AVFilter ff_vf_cas;
+extern const AVFilter ff_vf_ccrepack;
 extern const AVFilter ff_vf_chromaber_vulkan;
 extern const AVFilter ff_vf_chromahold;
 extern const AVFilter ff_vf_chromakey;
diff --git a/libavfilter/vf_ccrepack.c b/libavfilter/vf_ccrepack.c
new file mode 100644
index 0000000..c6819b8
--- /dev/null
+++ b/libavfilter/vf_ccrepack.c
@@ -0,0 +1,100 @@
+/*
+ * CEA-708 Closed Caption Repacker
+ * Copyright (c) 2023 LTN Global Communications
+ *
+ * Author: Devin Heitmueller <dheitmueller@ltnglobal.com>
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+/*
+ * Repackage CEA-708 arrays, which deals with incorrect cc_count for a given
+ * output framerate, and incorrect 708 padding.
+ *
+ * See CEA CEA-10-A "EIA-708-B Implementation Guidance", Section 26.5
+ * "Grouping DTVCC Data Within user_data() Structure"
+ */
+
+#include "avfilter.h"
+#include "internal.h"
+#include "ccfifo.h"
+#include "libavutil/opt.h"
+
+typedef struct CCRepackContext
+{
+    const AVClass *class;
+    AVCCFifo *cc_fifo;
+} CCRepackContext;
+
+static const AVOption ccrepack_options[] = {
+    {  NULL }
+};
+
+AVFILTER_DEFINE_CLASS(ccrepack);
+
+static int config_input(AVFilterLink *link)
+{
+    CCRepackContext *ctx = link->dst->priv;
+
+    if (!(ctx->cc_fifo = ff_ccfifo_alloc(&link->frame_rate, ctx)))
+        av_log(ctx, AV_LOG_VERBOSE, "Failure to setup CC FIFO queue.  Captions will be passed through\n");
+
+    return 0;
+}
+
+static int filter_frame(AVFilterLink *inlink, AVFrame *frame)
+{
+    CCRepackContext *ctx = inlink->dst->priv;
+    AVFilterLink *outlink = inlink->dst->outputs[0];
+
+    ff_ccfifo_extract(ctx->cc_fifo, frame);
+    ff_ccfifo_inject(ctx->cc_fifo, frame);
+
+    return ff_filter_frame(outlink, frame);
+}
+
+static av_cold void uninit(AVFilterContext *ctx)
+{
+    CCRepackContext *s = ctx->priv;
+    ff_ccfifo_freep(&s->cc_fifo);
+}
+
+static const AVFilterPad avfilter_vf_ccrepack_inputs[] = {
+    {
+        .name         = "default",
+        .type         = AVMEDIA_TYPE_VIDEO,
+        .filter_frame = filter_frame,
+	.config_props = config_input,
+    },
+};
+
+static const AVFilterPad avfilter_vf_ccrepack_outputs[] = {
+    {
+        .name = "default",
+        .type = AVMEDIA_TYPE_VIDEO,
+    },
+};
+
+AVFilter ff_vf_ccrepack = {
+    .name        = "ccrepack",
+    .description = NULL_IF_CONFIG_SMALL("Repack CEA-708 closed caption metadata"),
+    .uninit      = uninit,
+    .priv_size   = sizeof(CCRepackContext),
+    .priv_class  = &ccrepack_class,
+    FILTER_INPUTS(avfilter_vf_ccrepack_inputs),
+    FILTER_OUTPUTS(avfilter_vf_ccrepack_outputs),
+};
-- 
1.8.3.1

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Re: [FFmpeg-devel] [PATCH v3 1/5] ccfifo: Properly handle CEA-708 captions through framerate conversion

[Lance Wang]

On Fri, Apr 21, 2023 at 9:29 PM Devin Heitmueller <
devin.heitmueller@ltnglobal.com> wrote:

> When transcoding video that contains 708 closed captions, the
> caption data is tied to the frames as side data.  Simply dropping
> or adding frames to change the framerate will result in loss of
> data, so the caption data needs to be preserved and reformatted.
>
> For example, without this patch converting 720p59 to 1080i59
> would result in loss of 50% of the caption bytes, resulting in
> garbled 608 captions and 708 probably wouldn't render at all.
> Further, the frames that are there will have an illegal
> cc_count for the target framerate, so some decoders may ignore
> the packets entirely.
>
> Extract the 608 and 708 tuples and insert them onto queues.  Then
> after dropping/adding frames, re-write the tuples back into the
> resulting frames at the appropriate rate given the target
> framerate.  This includes both having the correct cc_count as
> well as clocking out the 608 pairs at the appropriate rate.
>
> Signed-off-by: Devin Heitmueller <dheitmueller@ltnglobal.com>
> ---
>  libavfilter/Makefile |   1 +
>  libavfilter/ccfifo.c | 191
> +++++++++++++++++++++++++++++++++++++++++++++++++++
>  libavfilter/ccfifo.h |  85 +++++++++++++++++++++++
>  3 files changed, 277 insertions(+)
>  create mode 100644 libavfilter/ccfifo.c
>  create mode 100644 libavfilter/ccfifo.h
>
> diff --git a/libavfilter/Makefile b/libavfilter/Makefile
> index 71e198b..628ade8 100644
> --- a/libavfilter/Makefile
> +++ b/libavfilter/Makefile
> @@ -14,6 +14,7 @@ OBJS = allfilters.o
>                \
>         buffersink.o                                                     \
>         buffersrc.o                                                      \
>         colorspace.o                                                     \
> +       ccfifo.o                                                         \
>         drawutils.o                                                      \
>         fifo.o                                                           \
>         formats.o                                                        \
> diff --git a/libavfilter/ccfifo.c b/libavfilter/ccfifo.c
> new file mode 100644
> index 0000000..3f8be57
> --- /dev/null
> +++ b/libavfilter/ccfifo.c
> @@ -0,0 +1,191 @@
> +/*
> + * CEA-708 Closed Captioning FIFO
> + * Copyright (c) 2023 LTN Global Communications
> + *
> + * Author: Devin Heitmueller <dheitmueller@ltnglobal.com>
> + *
> + * This file is part of FFmpeg.
> + *
> + * FFmpeg is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU Lesser General Public
> + * License as published by the Free Software Foundation; either
> + * version 2.1 of the License, or (at your option) any later version.
> + *
> + * FFmpeg is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> + * Lesser General Public License for more details.
> + *
> + * You should have received a copy of the GNU Lesser General Public
> + * License along with FFmpeg; if not, write to the Free Software
> + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
> 02110-1301 USA
> + */
> +
> +#include "ccfifo.h"
> +
> +struct AVCCFifo {
> +    AVFifo *cc_608_fifo;
> +    AVFifo *cc_708_fifo;
> +    int expected_cc_count;
> +    int expected_608;
> +    int cc_detected;
> +    void *log_ctx;
> +};
> +
> +#define MAX_CC_ELEMENTS 128
> +#define CC_BYTES_PER_ENTRY 3
> +
> +struct cc_lookup {
> +    int num;
> +    int den;
> +    int cc_count;
> +    int num_608;
> +};
> +
> +const static struct cc_lookup cc_lookup_vals[] = {
> +    { 15, 1, 40, 4 },
> +    { 24, 1, 25, 3 },
> +    { 24000, 1001, 25, 3 },
> +    { 30, 1, 20, 2 },
> +    { 30000, 1001, 20, 2},
> +    { 60, 1, 10, 1 },
> +    { 60000, 1001, 10, 1},
> +};
> +
> +void ff_ccfifo_freep(AVCCFifo **ccf)
> +{
> +    if (ccf && *ccf) {
> +        AVCCFifo *tmp = *ccf;
> +        if (tmp->cc_608_fifo)
> +            av_fifo_freep2(&tmp->cc_608_fifo);
> +        if (tmp->cc_708_fifo)
> +            av_fifo_freep2(&tmp->cc_708_fifo);
> +        av_freep(*ccf);
> +    }
> +}
> +
> +AVCCFifo *ff_ccfifo_alloc(AVRational *framerate, void *log_ctx)
> +{
> +    AVCCFifo *ccf;
> +    int i;
> +
> +    ccf = av_mallocz(sizeof(*ccf));
> +    if (!ccf)
> +        return NULL;
> +
> +    if (!(ccf->cc_708_fifo = av_fifo_alloc2(MAX_CC_ELEMENTS,
> CC_BYTES_PER_ENTRY, 0)))
> +        goto error;
> +
> +    if (!(ccf->cc_608_fifo = av_fifo_alloc2(MAX_CC_ELEMENTS,
> CC_BYTES_PER_ENTRY, 0)))
> +        goto error;
> +
> +    /* Based on the target FPS, figure out the expected cc_count and
> number of
> +       608 tuples per packet.  See ANSI/CTA-708-E Sec 4.3.6.1. */
> +    for (i = 0; i < (sizeof(cc_lookup_vals) / sizeof(struct cc_lookup));
> i++) {
>

I prefer to use FF_ARRAY_ELEMS here.


> +        if (framerate->num == cc_lookup_vals[i].num &&
> +            framerate->den == cc_lookup_vals[i].den) {
> +            ccf->expected_cc_count = cc_lookup_vals[i].cc_count;
> +            ccf->expected_608 = cc_lookup_vals[i].num_608;
> +            break;
> +        }
> +    }
> +
> +    if (ccf->expected_608 == 0) {
> +        av_log(ccf->log_ctx, AV_LOG_WARNING, "cc_fifo cannot transcode
> captions fps=%d/%d\n",
> +               framerate->num, framerate->den);
> +        return NULL;
>

why not use goto error?  I feel ccf should be freed.


> +    }
> +
> +    return ccf;
> +
> +error:
> +    ff_ccfifo_freep(&ccf);
> +    return NULL;
> +}
> +
> +int ff_ccfifo_inject(AVCCFifo *ccf, AVFrame *frame)
> +{
> +    AVFrameSideData *sd;
> +    int cc_filled = 0;
> +    int i;
> +
> +    if (!ccf)
> +        return 0;
>

+ * @return            Zero on success, or negative AVERROR
+ *                    code on failure.

 why not return error code?  the same to other failure condition.

+
> +    if (ccf->cc_detected == 0 || ccf->expected_cc_count == 0)
> +        return 0;
> +
> +    sd = av_frame_new_side_data(frame, AV_FRAME_DATA_A53_CC,
> +                                ccf->expected_cc_count *
> CC_BYTES_PER_ENTRY);
> +    if (!sd)
> +        return 0;
>

same.


> +
> +    for (i = 0; i < ccf->expected_608; i++) {
> +        if (av_fifo_can_read(ccf->cc_608_fifo) >= CC_BYTES_PER_ENTRY) {
> +            av_fifo_read(ccf->cc_608_fifo, &sd->data[cc_filled *
> CC_BYTES_PER_ENTRY],
> +                         CC_BYTES_PER_ENTRY);
> +            cc_filled++;
> +        } else {
> +            break;
> +        }
> +    }
> +
> +    /* Insert any available data from the 708 FIFO */
> +    while (cc_filled < ccf->expected_cc_count) {
> +        if (av_fifo_can_read(ccf->cc_708_fifo) >= CC_BYTES_PER_ENTRY) {
> +            av_fifo_read(ccf->cc_708_fifo, &sd->data[cc_filled *
> CC_BYTES_PER_ENTRY],
> +                         CC_BYTES_PER_ENTRY);
> +            cc_filled++;
> +        } else {
> +            break;
> +        }
> +    }
> +
> +    /* Insert 708 padding into any remaining fields */
> +    while (cc_filled < ccf->expected_cc_count) {
> +        sd->data[cc_filled * CC_BYTES_PER_ENTRY]     = 0xfa;
> +        sd->data[cc_filled * CC_BYTES_PER_ENTRY + 1] = 0x00;
> +        sd->data[cc_filled * CC_BYTES_PER_ENTRY + 2] = 0x00;
> +        cc_filled++;
> +    }
> +
> +    return 0;
> +}
> +
> +int ff_ccfifo_extract(AVCCFifo *ccf, AVFrame *frame)
> +{
> +    int i;
> +
> +    if (!ccf)
> +        return 0;
>

+ * @return            Zero on success, or negative AVERROR
+ *                    code on failure.
same question.


> +
> +    /* Read the A53 side data, discard padding, and put 608/708 into
> +       queues so we can ensure they get into the output frames at
> +       the correct rate... */
> +    if (ccf->expected_cc_count > 0) {
> +        AVFrameSideData *side_data = av_frame_get_side_data(frame,
> AV_FRAME_DATA_A53_CC);
> +        if (side_data) {
> +            uint8_t *cc_bytes = side_data->data;
> +            int cc_count = side_data->size / CC_BYTES_PER_ENTRY;
> +            ccf->cc_detected = 1;
> +
> +            for (i = 0; i < cc_count; i++) {
> +                /* See ANSI/CTA-708-E Sec 4.3, Table 3 */
> +                uint8_t cc_valid = (cc_bytes[CC_BYTES_PER_ENTRY*i] &
> 0x04) >> 2;
> +                uint8_t cc_type = cc_bytes[CC_BYTES_PER_ENTRY*i] & 0x03;
> +                if (cc_type == 0x00 || cc_type == 0x01) {
> +                    av_fifo_write(ccf->cc_608_fifo,
> &cc_bytes[CC_BYTES_PER_ENTRY*i],
> +                                  CC_BYTES_PER_ENTRY);
> +                } else if (cc_valid && (cc_type == 0x02 || cc_type ==
> 0x03)) {
> +                    av_fifo_write(ccf->cc_708_fifo,
> &cc_bytes[CC_BYTES_PER_ENTRY*i],
> +                                  CC_BYTES_PER_ENTRY);
> +                }
> +            }
> +
> +            /* Remove the side data, as we will re-create it on the
> +               output as needed */
> +            av_frame_remove_side_data(frame, AV_FRAME_DATA_A53_CC);
> +        }
> +    }
> +    return 0;
> +}
> diff --git a/libavfilter/ccfifo.h b/libavfilter/ccfifo.h
> new file mode 100644
> index 0000000..70e8b9b
> --- /dev/null
> +++ b/libavfilter/ccfifo.h
> @@ -0,0 +1,85 @@
> +/*
> + * CEA-708 Closed Captioning FIFO
> + * Copyright (c) 2023 LTN Global Communications
> + *
> + * Author: Devin Heitmueller <dheitmueller@ltnglobal.com>
> + *
> + * This file is part of FFmpeg.
> + *
> + * FFmpeg is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU Lesser General Public
> + * License as published by the Free Software Foundation; either
> + * version 2.1 of the License, or (at your option) any later version.
> + *
> + * FFmpeg is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> + * Lesser General Public License for more details.
> + *
> + * You should have received a copy of the GNU Lesser General Public
> + * License along with FFmpeg; if not, write to the Free Software
> + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
> 02110-1301 USA
> + */
> +
> +/**
> + * @file
> + * CC FIFO Buffer
> + */
> +
> +#ifndef AVUTIL_CCFIFO_H
> +#define AVUTIL_CCFIFO_H
>

AVUTIL is wrong here


> +
> +#include "libavutil/avutil.h"
> +#include "libavutil/frame.h"
> +#include "libavutil/fifo.h"
> +
> +typedef struct AVCCFifo AVCCFifo;
> +
> +/**
> + * Allocate an AVCCFifo.
> + *
> + * @param sample_fmt  sample format
> + * @param channels    number of channels
> + * @param nb_samples  initial allocation size, in samples
>

This is mismatch comments


> + * @return            newly allocated AVCCFifo, or NULL on error
> + */
> +AVCCFifo *ff_ccfifo_alloc(AVRational *framerate, void *log_ctx);
> +
> +/**
> + * Free an AVCCFifo
> + *
> + * @param ccf Pointer to the pointer to the AVCCFifo which should be freed
> + * @note `*ptr = NULL` is safe and leads to no action.
> + */
> +void ff_ccfifo_freep(AVCCFifo **ccf);
> +
> +
> +/**
> + * Read a frame into a CC Fifo
>

It's not clear I think.


> + *
> + * Extract CC bytes from the AVFrame, insert them into our queue, and
> + * remove the side data from the AVFrame.  The side data is removed
> + * as it will be re-inserted at the appropriate rate later in the
> + * filter.
> + *
> + * @param af          AVCCFifo to write to
> + * @param frame       AVFrame with the video frame to operate on
> + * @return            Zero on success, or negative AVERROR
> + *                    code on failure.
> + */
> +int ff_ccfifo_extract(AVCCFifo *af, AVFrame *frame);
> +
> +/**
> + * Insert CC data from the FIFO into an AVFrame (as side data)
> + *
> + * Dequeue the appropriate number of CC tuples based on the
> + * frame rate, and insert them into the AVFrame
> + *
> + * @param af          AVCCFifo to read from
> + * @param frame       AVFrame with the video frame to operate on
> + * @return            Zero on success, or negative AVERROR
> + *                    code on failure.
> + */
> +int ff_ccfifo_inject(AVCCFifo *af, AVFrame *frame);
> +
> +#endif /* AVUTIL_CCFIFO_H */
> --
> 1.8.3.1
>
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Re: [FFmpeg-devel] [PATCH v3 1/5] ccfifo: Properly handle CEA-708 captions through framerate conversion

[Devin Heitmueller]

Hi Lance,

Thank you for your review.  Comments inline.

On Tue, Apr 25, 2023 at 10:28 AM Lance Wang <lance.lmwang@gmail.com> wrote:
> > +    /* Based on the target FPS, figure out the expected cc_count and
> > number of
> > +       608 tuples per packet.  See ANSI/CTA-708-E Sec 4.3.6.1. */
> > +    for (i = 0; i < (sizeof(cc_lookup_vals) / sizeof(struct cc_lookup));
> > i++) {
> >
>
> I prefer to use FF_ARRAY_ELEMS here.

Ok.

> > +        if (framerate->num == cc_lookup_vals[i].num &&
> > +            framerate->den == cc_lookup_vals[i].den) {
> > +            ccf->expected_cc_count = cc_lookup_vals[i].cc_count;
> > +            ccf->expected_608 = cc_lookup_vals[i].num_608;
> > +            break;
> > +        }
> > +    }
> > +
> > +    if (ccf->expected_608 == 0) {
> > +        av_log(ccf->log_ctx, AV_LOG_WARNING, "cc_fifo cannot transcode
> > captions fps=%d/%d\n",
> > +               framerate->num, framerate->den);
> > +        return NULL;
> >
>
> why not use goto error?  I feel ccf should be freed.

Good point.  I'll fix that.

>
>
> > +    }
> > +
> > +    return ccf;
> > +
> > +error:
> > +    ff_ccfifo_freep(&ccf);
> > +    return NULL;
> > +}
> > +
> > +int ff_ccfifo_inject(AVCCFifo *ccf, AVFrame *frame)
> > +{
> > +    AVFrameSideData *sd;
> > +    int cc_filled = 0;
> > +    int i;
> > +
> > +    if (!ccf)
> > +        return 0;
> >
>
> + * @return            Zero on success, or negative AVERROR
> + *                    code on failure.
>
>  why not return error code?  the same to other failure condition.

Ok, so there are legal cases where ccf is NULL and it isn't an error
condition.  If the creation of the FIFO fails due to an unsupported
output framerate, the expectation is that you can continue to call the
inject/extract functions and they will simply do nothing (i.e. it will
work in passthrough mode).  There are two alternatives to this
approach:

1.  Continue to have the FIFO creation fail (returning a NULL
pointer), and then have to make sure every caller of extract/inject
checks for the NULL pointer prior to calling the function.

2.  Have the FIFO creation report the warning but "succeed" and create
the FIFO, and then have the inject/extract functions check some flag
within the ccf structure and do nothing if the flag is set.

I'm open to ideas on the best approach here.

> +
> > +    if (ccf->cc_detected == 0 || ccf->expected_cc_count == 0)
> > +        return 0;
> > +
> > +    sd = av_frame_new_side_data(frame, AV_FRAME_DATA_A53_CC,
> > +                                ccf->expected_cc_count *
> > CC_BYTES_PER_ENTRY);
> > +    if (!sd)
> > +        return 0;
> >
>
> same.

Ok.

> > +int ff_ccfifo_extract(AVCCFifo *ccf, AVFrame *frame)
> > +{
> > +    int i;
> > +
> > +    if (!ccf)
> > +        return 0;
> >
>
> + * @return            Zero on success, or negative AVERROR
> + *                    code on failure.
> same question.

Same explanation as for ff_ccfifo_inject() above,

> > +#ifndef AVUTIL_CCFIFO_H
> > +#define AVUTIL_CCFIFO_H
> >
>
> AVUTIL is wrong here

Ok.

>
> > +
> > +#include "libavutil/avutil.h"
> > +#include "libavutil/frame.h"
> > +#include "libavutil/fifo.h"
> > +
> > +typedef struct AVCCFifo AVCCFifo;
> > +
> > +/**
> > + * Allocate an AVCCFifo.
> > + *
> > + * @param sample_fmt  sample format
> > + * @param channels    number of channels
> > + * @param nb_samples  initial allocation size, in samples
> >
>
> This is mismatch comments

Ok.

> > + * @return            newly allocated AVCCFifo, or NULL on error
> > + */
> > +AVCCFifo *ff_ccfifo_alloc(AVRational *framerate, void *log_ctx);
> > +
> > +/**
> > + * Free an AVCCFifo
> > + *
> > + * @param ccf Pointer to the pointer to the AVCCFifo which should be freed
> > + * @note `*ptr = NULL` is safe and leads to no action.
> > + */
> > +void ff_ccfifo_freep(AVCCFifo **ccf);
> > +
> > +
> > +/**
> > + * Read a frame into a CC Fifo
> >
>
> It's not clear I think.

I don't love the "inject/extract" naming, but I couldn't think of a
better name (I've actually renamed those functions a couple of times
over the years I had this code in a non-upstream tree).  In particular
because the extract function both extracts/removes the bytes from the
frame and inserts them into the queue, the naming can be a bit
confusing (and vice versa for the inject function).

I welcome suggestions on a better name that more clearly describes
what the two functions do.

Again, thanks for your comments.  The majority of the issues you
raised are simple enough to fix, and I welcome suggestions on the
others.

Devin

-- 
Devin Heitmueller, Senior Software Engineer
LTN Global Communications
o: +1 (301) 363-1001
w: https://ltnglobal.com  e: devin.heitmueller@ltnglobal.com
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Re: [FFmpeg-devel] [PATCH v3 1/5] ccfifo: Properly handle CEA-708 captions through framerate conversion

[Lance Wang]

On Wed, Apr 26, 2023 at 10:14 PM Devin Heitmueller <
devin.heitmueller@ltnglobal.com> wrote:

> Hi Lance,
>
> Thank you for your review.  Comments inline.
>
> On Tue, Apr 25, 2023 at 10:28 AM Lance Wang <lance.lmwang@gmail.com>
> wrote:
> > > +    /* Based on the target FPS, figure out the expected cc_count and
> > > number of
> > > +       608 tuples per packet.  See ANSI/CTA-708-E Sec 4.3.6.1. */
> > > +    for (i = 0; i < (sizeof(cc_lookup_vals) / sizeof(struct
> cc_lookup));
> > > i++) {
> > >
> >
> > I prefer to use FF_ARRAY_ELEMS here.
>
> Ok.
>
> > > +        if (framerate->num == cc_lookup_vals[i].num &&
> > > +            framerate->den == cc_lookup_vals[i].den) {
> > > +            ccf->expected_cc_count = cc_lookup_vals[i].cc_count;
> > > +            ccf->expected_608 = cc_lookup_vals[i].num_608;
> > > +            break;
> > > +        }
> > > +    }
> > > +
> > > +    if (ccf->expected_608 == 0) {
> > > +        av_log(ccf->log_ctx, AV_LOG_WARNING, "cc_fifo cannot transcode
> > > captions fps=%d/%d\n",
> > > +               framerate->num, framerate->den);
> > > +        return NULL;
> > >
> >
> > why not use goto error?  I feel ccf should be freed.
>
> Good point.  I'll fix that.
>
> >
> >
> > > +    }
> > > +
> > > +    return ccf;
> > > +
> > > +error:
> > > +    ff_ccfifo_freep(&ccf);
> > > +    return NULL;
> > > +}
> > > +
> > > +int ff_ccfifo_inject(AVCCFifo *ccf, AVFrame *frame)
> > > +{
> > > +    AVFrameSideData *sd;
> > > +    int cc_filled = 0;
> > > +    int i;
> > > +
> > > +    if (!ccf)
> > > +        return 0;
> > >
> >
> > + * @return            Zero on success, or negative AVERROR
> > + *                    code on failure.
> >
> >  why not return error code?  the same to other failure condition.
>
> Ok, so there are legal cases where ccf is NULL and it isn't an error
> condition.  If the creation of the FIFO fails due to an unsupported
> output framerate, the expectation is that you can continue to call the
> inject/extract functions and they will simply do nothing (i.e. it will
> work in passthrough mode).  There are two alternatives to this
> approach:
>
> 1.  Continue to have the FIFO creation fail (returning a NULL
> pointer), and then have to make sure every caller of extract/inject
> checks for the NULL pointer prior to calling the function.
>
> 2.  Have the FIFO creation report the warning but "succeed" and create
> the FIFO, and then have the inject/extract functions check some flag
> within the ccf structure and do nothing if the flag is set.
>
>
I prefer to 2

I'm open to ideas on the best approach here.
>
> > +
> > > +    if (ccf->cc_detected == 0 || ccf->expected_cc_count == 0)
> > > +        return 0;
> > > +
> > > +    sd = av_frame_new_side_data(frame, AV_FRAME_DATA_A53_CC,
> > > +                                ccf->expected_cc_count *
> > > CC_BYTES_PER_ENTRY);
> > > +    if (!sd)
> > > +        return 0;
> > >
> >
> > same.
>
> Ok.
>
> > > +int ff_ccfifo_extract(AVCCFifo *ccf, AVFrame *frame)
> > > +{
> > > +    int i;
> > > +
> > > +    if (!ccf)
> > > +        return 0;
> > >
> >
> > + * @return            Zero on success, or negative AVERROR
> > + *                    code on failure.
> > same question.
>
> Same explanation as for ff_ccfifo_inject() above,
>
> > > +#ifndef AVUTIL_CCFIFO_H
> > > +#define AVUTIL_CCFIFO_H
> > >
> >
> > AVUTIL is wrong here
>
> Ok.
>
> >
> > > +
> > > +#include "libavutil/avutil.h"
> > > +#include "libavutil/frame.h"
> > > +#include "libavutil/fifo.h"
> > > +
> > > +typedef struct AVCCFifo AVCCFifo;
> > > +
> > > +/**
> > > + * Allocate an AVCCFifo.
> > > + *
> > > + * @param sample_fmt  sample format
> > > + * @param channels    number of channels
> > > + * @param nb_samples  initial allocation size, in samples
> > >
> >
> > This is mismatch comments
>
> Ok.
>
> > > + * @return            newly allocated AVCCFifo, or NULL on error
> > > + */
> > > +AVCCFifo *ff_ccfifo_alloc(AVRational *framerate, void *log_ctx);
> > > +
> > > +/**
> > > + * Free an AVCCFifo
> > > + *
> > > + * @param ccf Pointer to the pointer to the AVCCFifo which should be
> freed
> > > + * @note `*ptr = NULL` is safe and leads to no action.
> > > + */
> > > +void ff_ccfifo_freep(AVCCFifo **ccf);
> > > +
> > > +
> > > +/**
> > > + * Read a frame into a CC Fifo
> > >
> >
> > It's not clear I think.
>
> I don't love the "inject/extract" naming, but I couldn't think of a
> better name (I've actually renamed those functions a couple of times
> over the years I had this code in a non-upstream tree).  In particular
> because the extract function both extracts/removes the bytes from the
> frame and inserts them into the queue, the naming can be a bit
> confusing (and vice versa for the inject function).
>

I only think the comments "Read a frame into a CC fifo" isn't clear for the
function, I'm OK with the function name.



> I welcome suggestions on a better name that more clearly describes
> what the two functions do.
>
> Again, thanks for your comments.  The majority of the issues you
> raised are simple enough to fix, and I welcome suggestions on the
> others.
>
> Devin
>
> --
> Devin Heitmueller, Senior Software Engineer
> LTN Global Communications
> o: +1 (301) 363-1001
> w: https://ltnglobal.com  e: devin.heitmueller@ltnglobal.com
> _______________________________________________
> ffmpeg-devel mailing list
> ffmpeg-devel@ffmpeg.org
> https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
>
> To unsubscribe, visit link above, or email
> ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".
>
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