[FFmpeg-devel] [PATCH] avdevice/lavfi: output wrapped AVFrames

[Timo Rothenpieler <timo@rothenpieler.org>]

This avoids an extra copy of potentially quite big video frames.
Instead of copying the entire frames data into a rawvideo packet it
packs the frame into a wrapped avframe packet and passes it through
as-is.
Unfortunately, wrapped avframes are set up to be video frames, so the
audio frames unfortunately continue to be copied.

Additionally, this enabled passing through video frames that previously
were impossible to process, like hardware frames or other special
formats that couldn't be packed into a rawvideo packet.
---
 libavdevice/lavfi.c                       | 87 +++++++++--------------
 tests/ref/fate/filter-metadata-cropdetect |  3 +-
 2 files changed, 36 insertions(+), 54 deletions(-)

diff --git a/libavdevice/lavfi.c b/libavdevice/lavfi.c
index db5d0b94de..61076f9950 100644
--- a/libavdevice/lavfi.c
+++ b/libavdevice/lavfi.c
@@ -54,32 +54,10 @@ typedef struct {
     int *sink_eof;
     int *stream_sink_map;
     int *sink_stream_subcc_map;
-    AVFrame *decoded_frame;
     int nb_sinks;
     AVPacket subcc_packet;
 } LavfiContext;
 
-static int *create_all_formats(int n)
-{
-    int i, j, *fmts, count = 0;
-
-    for (i = 0; i < n; i++) {
-        const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(i);
-        if (!(desc->flags & AV_PIX_FMT_FLAG_HWACCEL))
-            count++;
-    }
-
-    if (!(fmts = av_malloc_array(count + 1, sizeof(*fmts))))
-        return NULL;
-    for (j = 0, i = 0; i < n; i++) {
-        const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(i);
-        if (!(desc->flags & AV_PIX_FMT_FLAG_HWACCEL))
-            fmts[j++] = i;
-    }
-    fmts[j] = AV_PIX_FMT_NONE;
-    return fmts;
-}
-
 av_cold static int lavfi_read_close(AVFormatContext *avctx)
 {
     LavfiContext *lavfi = avctx->priv_data;
@@ -90,7 +68,6 @@ av_cold static int lavfi_read_close(AVFormatContext *avctx)
     av_freep(&lavfi->sink_stream_subcc_map);
     av_freep(&lavfi->sinks);
     avfilter_graph_free(&lavfi->graph);
-    av_frame_free(&lavfi->decoded_frame);
 
     return 0;
 }
@@ -125,15 +102,11 @@ av_cold static int lavfi_read_header(AVFormatContext *avctx)
     LavfiContext *lavfi = avctx->priv_data;
     AVFilterInOut *input_links = NULL, *output_links = NULL, *inout;
     const AVFilter *buffersink, *abuffersink;
-    int *pix_fmts = create_all_formats(AV_PIX_FMT_NB);
     enum AVMediaType type;
     int ret = 0, i, n;
 
 #define FAIL(ERR) { ret = ERR; goto end; }
 
-    if (!pix_fmts)
-        FAIL(AVERROR(ENOMEM));
-
     buffersink = avfilter_get_by_name("buffersink");
     abuffersink = avfilter_get_by_name("abuffersink");
 
@@ -264,8 +237,6 @@ av_cold static int lavfi_read_header(AVFormatContext *avctx)
             ret = avfilter_graph_create_filter(&sink, buffersink,
                                                inout->name, NULL,
                                                NULL, lavfi->graph);
-            if (ret >= 0)
-                ret = av_opt_set_int_list(sink, "pix_fmts", pix_fmts,  AV_PIX_FMT_NONE, AV_OPT_SEARCH_CHILDREN);
             if (ret < 0)
                 goto end;
         } else if (type == AVMEDIA_TYPE_AUDIO) {
@@ -321,15 +292,11 @@ av_cold static int lavfi_read_header(AVFormatContext *avctx)
         avpriv_set_pts_info(st, 64, time_base.num, time_base.den);
         par->codec_type = av_buffersink_get_type(sink);
         if (par->codec_type == AVMEDIA_TYPE_VIDEO) {
-            int64_t probesize;
-            par->codec_id   = AV_CODEC_ID_RAWVIDEO;
+            par->codec_id   = AV_CODEC_ID_WRAPPED_AVFRAME;
             par->format     = av_buffersink_get_format(sink);
             par->width      = av_buffersink_get_w(sink);
             par->height     = av_buffersink_get_h(sink);
-            probesize       = par->width * par->height * 30 *
-                              av_get_padded_bits_per_pixel(av_pix_fmt_desc_get(par->format));
-            avctx->probesize = FFMAX(avctx->probesize, probesize);
-            st       ->sample_aspect_ratio =
+            st ->sample_aspect_ratio =
             par->sample_aspect_ratio = av_buffersink_get_sample_aspect_ratio(sink);
         } else if (par->codec_type == AVMEDIA_TYPE_AUDIO) {
             par->sample_rate = av_buffersink_get_sample_rate(sink);
@@ -348,11 +315,7 @@ av_cold static int lavfi_read_header(AVFormatContext *avctx)
     if ((ret = create_subcc_streams(avctx)) < 0)
         goto end;
 
-    if (!(lavfi->decoded_frame = av_frame_alloc()))
-        FAIL(AVERROR(ENOMEM));
-
 end:
-    av_free(pix_fmts);
     avfilter_inout_free(&input_links);
     avfilter_inout_free(&output_links);
     return ret;
@@ -378,15 +341,20 @@ static int create_subcc_packet(AVFormatContext *avctx, AVFrame *frame,
     return 0;
 }
 
+static void lavfi_free_frame(void *opaque, uint8_t *data)
+{
+    AVFrame *frame = (AVFrame*)data;
+    av_frame_free(&frame);
+}
+
 static int lavfi_read_packet(AVFormatContext *avctx, AVPacket *pkt)
 {
     LavfiContext *lavfi = avctx->priv_data;
     double min_pts = DBL_MAX;
     int stream_idx, min_pts_sink_idx = 0;
-    AVFrame *frame = lavfi->decoded_frame;
+    AVFrame *frame;
     AVDictionary *frame_metadata;
     int ret, i;
-    int size = 0;
     AVStream *st;
 
     if (lavfi->subcc_packet.size) {
@@ -394,6 +362,10 @@ static int lavfi_read_packet(AVFormatContext *avctx, AVPacket *pkt)
         return pkt->size;
     }
 
+    frame = av_frame_alloc();
+    if (!frame)
+        return AVERROR(ENOMEM);
+
     /* iterate through all the graph sinks. Select the sink with the
      * minimum PTS */
     for (i = 0; i < lavfi->nb_sinks; i++) {
@@ -411,7 +383,7 @@ static int lavfi_read_packet(AVFormatContext *avctx, AVPacket *pkt)
             lavfi->sink_eof[i] = 1;
             continue;
         } else if (ret < 0)
-            return ret;
+            goto fail;
         d = av_rescale_q_rnd(frame->pts, tb, AV_TIME_BASE_Q, AV_ROUND_NEAR_INF|AV_ROUND_PASS_MINMAX);
         ff_dlog(avctx, "sink_idx:%d time:%f\n", i, d);
         av_frame_unref(frame);
@@ -421,8 +393,10 @@ static int lavfi_read_packet(AVFormatContext *avctx, AVPacket *pkt)
             min_pts_sink_idx = i;
         }
     }
-    if (min_pts == DBL_MAX)
-        return AVERROR_EOF;
+    if (min_pts == DBL_MAX) {
+        ret = AVERROR_EOF;
+        goto fail;
+    }
 
     ff_dlog(avctx, "min_pts_sink_idx:%i\n", min_pts_sink_idx);
 
@@ -431,15 +405,19 @@ static int lavfi_read_packet(AVFormatContext *avctx, AVPacket *pkt)
     st = avctx->streams[stream_idx];
 
     if (st->codecpar->codec_type == AVMEDIA_TYPE_VIDEO) {
-        size = av_image_get_buffer_size(frame->format, frame->width, frame->height, 1);
-        if ((ret = av_new_packet(pkt, size)) < 0)
+        pkt->buf = av_buffer_create((uint8_t*)frame, sizeof(*frame),
+                                    &lavfi_free_frame, NULL, 0);
+        if (!pkt->buf) {
+            ret = AVERROR(ENOMEM);
             goto fail;
+        }
 
-        av_image_copy_to_buffer(pkt->data, size, (const uint8_t **)frame->data, frame->linesize,
-                                frame->format, frame->width, frame->height, 1);
+        pkt->data   = pkt->buf->data;
+        pkt->size   = pkt->buf->size;
+        pkt->flags |= AV_PKT_FLAG_TRUSTED;
     } else if (st->codecpar->codec_type == AVMEDIA_TYPE_AUDIO) {
-        size = frame->nb_samples * av_get_bytes_per_sample(frame->format) *
-                                   frame->ch_layout.nb_channels;
+        int size = frame->nb_samples * av_get_bytes_per_sample(frame->format) *
+                                       frame->ch_layout.nb_channels;
         if ((ret = av_new_packet(pkt, size)) < 0)
             goto fail;
         memcpy(pkt->data, frame->data[0], size);
@@ -468,10 +446,13 @@ static int lavfi_read_packet(AVFormatContext *avctx, AVPacket *pkt)
     pkt->stream_index = stream_idx;
     pkt->pts = frame->pts;
     pkt->pos = frame->pkt_pos;
-    av_frame_unref(frame);
-    return size;
+
+    if (st->codecpar->codec_type != AVMEDIA_TYPE_VIDEO)
+        av_frame_free(&frame);
+
+    return pkt->size;
 fail:
-    av_frame_unref(frame);
+    av_frame_free(&frame);
     return ret;
 
 }
diff --git a/tests/ref/fate/filter-metadata-cropdetect b/tests/ref/fate/filter-metadata-cropdetect
index e7c03ead4e..104acdd77f 100644
--- a/tests/ref/fate/filter-metadata-cropdetect
+++ b/tests/ref/fate/filter-metadata-cropdetect
@@ -1,4 +1,5 @@
-pts=0
+pts=0|
+
 pts=400
 pts=800|tag:lavfi.cropdetect.x1=0|tag:lavfi.cropdetect.x2=719|tag:lavfi.cropdetect.y1=61|tag:lavfi.cropdetect.y2=424|tag:lavfi.cropdetect.w=720|tag:lavfi.cropdetect.h=352|tag:lavfi.cropdetect.x=0|tag:lavfi.cropdetect.y=68
 pts=1200|tag:lavfi.cropdetect.x1=0|tag:lavfi.cropdetect.x2=719|tag:lavfi.cropdetect.y1=61|tag:lavfi.cropdetect.y2=424|tag:lavfi.cropdetect.w=720|tag:lavfi.cropdetect.h=352|tag:lavfi.cropdetect.x=0|tag:lavfi.cropdetect.y=68
-- 
2.34.1

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