[FFmpeg-devel] [PATCH 1/3] fftools/ffmpeg_dec: improve detection of lavf-guessed durations

[FFmpeg-devel] [PATCH 1/3] fftools/ffmpeg_dec: improve detection of lavf-guessed durations

[Anton Khirnov]

Will be useful in following commit.
---
 fftools/ffmpeg_dec.c | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/fftools/ffmpeg_dec.c b/fftools/ffmpeg_dec.c
index 70de151301..c2bcf784b0 100644
--- a/fftools/ffmpeg_dec.c
+++ b/fftools/ffmpeg_dec.c
@@ -260,6 +260,10 @@ static int64_t video_duration_estimate(const DecoderPriv *dp, const AVFrame *fra
     const int  ts_unreliable = dp->flags & DECODER_FLAG_TS_UNRELIABLE;
     const int      fr_forced = dp->flags & DECODER_FLAG_FRAMERATE_FORCED;
     int64_t codec_duration = 0;
+    // difference between this and last frame's timestamps
+    const int64_t ts_diff =
+        (frame->pts != AV_NOPTS_VALUE && dp->last_frame_pts != AV_NOPTS_VALUE) ?
+        frame->pts - dp->last_frame_pts : -1;
 
     // XXX lavf currently makes up frame durations when they are not provided by
     // the container. As there is no way to reliably distinguish real container
@@ -267,8 +271,13 @@ static int64_t video_duration_estimate(const DecoderPriv *dp, const AVFrame *fra
     // the container has timestamps. Eventually lavf should stop making up
     // durations, then this should be simplified.
 
+    // frame duration is unreliable (typically guessed by lavf) when it is equal
+    // to 1 and the actual duration of the last frame is more than 2x larger
+    const int duration_unreliable = frame->duration == 1 && ts_diff > 2 * frame->duration;
+
     // prefer frame duration for containers with timestamps
-    if (frame->duration > 0 && (!ts_unreliable || fr_forced))
+    if (fr_forced ||
+        (frame->duration > 0 && !ts_unreliable && !duration_unreliable))
         return frame->duration;
 
     if (dp->dec_ctx->framerate.den && dp->dec_ctx->framerate.num) {
@@ -285,9 +294,8 @@ static int64_t video_duration_estimate(const DecoderPriv *dp, const AVFrame *fra
 
     // when timestamps are available, repeat last frame's actual duration
     // (i.e. pts difference between this and last frame)
-    if (frame->pts != AV_NOPTS_VALUE && dp->last_frame_pts != AV_NOPTS_VALUE &&
-        frame->pts > dp->last_frame_pts)
-        return frame->pts - dp->last_frame_pts;
+    if (ts_diff > 0)
+        return ts_diff;
 
     // try frame/codec duration
     if (frame->duration > 0)
-- 
2.43.0

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[FFmpeg-devel] [PATCH 2/3] fftools/ffmpeg_mux_init: default to input timebase for streamcopy

[Anton Khirnov]

Stop trying to invent some "framerate-based" timebase when there is no
reason to think the stream is CFR at all.
---
 fftools/ffmpeg_mux_init.c        | 7 +------
 tests/fate/ffmpeg.mak            | 2 +-
 tests/ref/fate/copy-trac4914-avi | 4 ++--
 3 files changed, 4 insertions(+), 9 deletions(-)

diff --git a/fftools/ffmpeg_mux_init.c b/fftools/ffmpeg_mux_init.c
index 899ee6046f..4a2b5924a4 100644
--- a/fftools/ffmpeg_mux_init.c
+++ b/fftools/ffmpeg_mux_init.c
@@ -960,17 +960,12 @@ static int streamcopy_init(const Muxer *mux, OutputStream *ost, AVDictionary **e
     else
         ost->st->avg_frame_rate = ist->st->avg_frame_rate;
 
-    ret = avformat_transfer_internal_stream_timing_info(mux->fc->oformat,
-                                                        ost->st, ist->st, copy_tb);
-    if (ret < 0)
-        goto fail;
-
     // copy timebase while removing common factors
     if (ost->st->time_base.num <= 0 || ost->st->time_base.den <= 0) {
         if (fr.num)
             ost->st->time_base = av_inv_q(fr);
         else
-            ost->st->time_base = av_add_q(av_stream_get_codec_timebase(ost->st), (AVRational){0, 1});
+            ost->st->time_base = av_add_q(ist->st->time_base, (AVRational){0, 1});
     }
 
     if (!ms->copy_prior_start) {
diff --git a/tests/fate/ffmpeg.mak b/tests/fate/ffmpeg.mak
index dc102750a0..9e0c68da20 100644
--- a/tests/fate/ffmpeg.mak
+++ b/tests/fate/ffmpeg.mak
@@ -146,7 +146,7 @@ fate-copy-trac236: CMD = transcode mov $(TARGET_SAMPLES)/mov/fcp_export8-236.mov
 
 FATE_STREAMCOPY-$(call TRANSCODE, RAWVIDEO MPEG2VIDEO, MXF, MPEGTS_DEMUXER MPEGVIDEO_PARSER MPEGAUDIO_PARSER MP2_DECODER ARESAMPLE_FILTER PCM_S16LE_DECODER) += fate-copy-trac4914
 fate-copy-trac4914: CMD = transcode mpegts $(TARGET_SAMPLES)/mpeg2/xdcam8mp2-1s_small.ts\
-                      mxf "-c:a pcm_s16le -af aresample -c:v copy"
+                      mxf "-c:a pcm_s16le -af aresample -c:v copy -time_base 1001/30000"
 
 FATE_STREAMCOPY-$(call TRANSCODE, RAWVIDEO MPEG2VIDEO, AVI, MPEGTS_DEMUXER MPEGVIDEO_PARSER MPEGAUDIO_PARSER EXTRACT_EXTRADATA_BSF MP2_DECODER ARESAMPLE_FILTER) += fate-copy-trac4914-avi
 fate-copy-trac4914-avi: CMD = transcode mpegts $(TARGET_SAMPLES)/mpeg2/xdcam8mp2-1s_small.ts\
diff --git a/tests/ref/fate/copy-trac4914-avi b/tests/ref/fate/copy-trac4914-avi
index 20006ea05c..d598e0aa65 100644
--- a/tests/ref/fate/copy-trac4914-avi
+++ b/tests/ref/fate/copy-trac4914-avi
@@ -1,5 +1,5 @@
-26e4202638bc384b82d2b5eb4d33a5f0 *tests/data/fate/copy-trac4914-avi.avi
-479494 tests/data/fate/copy-trac4914-avi.avi
+3b6f31b806ef421652a066f239536b0d *tests/data/fate/copy-trac4914-avi.avi
+492046 tests/data/fate/copy-trac4914-avi.avi
 #tb 0: 1001/30000
 #media_type 0: video
 #codec_id 0: rawvideo
-- 
2.43.0

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[FFmpeg-devel] [PATCH 3/3] lavf: deprecate avformat_transfer_internal_stream_timing_info()

[Anton Khirnov]

And av_stream_get_codec_timebase().

They were both added for ffmpeg CLI, which no longer calls either of
them. Furthermore the notion of "internal stream timing info" that needs
to be transferred with a special magic API function is fundamentally
flawed and should be removed.
---
 doc/APIchanges              |  4 ++++
 libavformat/avformat.c      |  2 ++
 libavformat/avformat.h      | 18 +++++++-----------
 libavformat/internal.h      |  2 ++
 libavformat/options.c       |  2 ++
 libavformat/version_major.h |  1 +
 6 files changed, 18 insertions(+), 11 deletions(-)

diff --git a/doc/APIchanges b/doc/APIchanges
index ac7953a49c..0dcb17eb35 100644
--- a/doc/APIchanges
+++ b/doc/APIchanges
@@ -2,6 +2,10 @@ The last version increases of all libraries were on 2024-03-07
 
 API changes, most recent first:
 
+2024-07-xx - xxxxxxxxxx - lavf 61 - avformat.h
+  Deprecate avformat_transfer_internal_stream_timing_info()
+  and av_stream_get_codec_timebase() without replacement.
+
 2024-07-02 - xxxxxxxxxx - lavu 59.28.100 - hwcontext_d3d12va.h
   Add AVD3D12VAFramesContext.flags
 
diff --git a/libavformat/avformat.c b/libavformat/avformat.c
index 140fb5b6aa..b4f20502fb 100644
--- a/libavformat/avformat.c
+++ b/libavformat/avformat.c
@@ -770,6 +770,7 @@ AVRational av_guess_frame_rate(AVFormatContext *format, AVStream *st, AVFrame *f
     return fr;
 }
 
+#if FF_API_INTERNAL_TIMING
 int avformat_transfer_internal_stream_timing_info(const AVOutputFormat *ofmt,
                                                   AVStream *ost, const AVStream *ist,
                                                   enum AVTimebaseSource copy_tb)
@@ -849,6 +850,7 @@ AVRational av_stream_get_codec_timebase(const AVStream *st)
 {
     return cffstream(st)->avctx ? cffstream(st)->avctx->time_base : cffstream(st)->transferred_mux_tb;
 }
+#endif
 
 void avpriv_set_pts_info(AVStream *st, int pts_wrap_bits,
                          unsigned int pts_num, unsigned int pts_den)
diff --git a/libavformat/avformat.h b/libavformat/avformat.h
index 8afdcd9fd0..90920072aa 100644
--- a/libavformat/avformat.h
+++ b/libavformat/avformat.h
@@ -3042,6 +3042,7 @@ int avformat_match_stream_specifier(AVFormatContext *s, AVStream *st,
 
 int avformat_queue_attached_pictures(AVFormatContext *s);
 
+#if FF_API_INTERNAL_TIMING
 enum AVTimebaseSource {
     AVFMT_TBCF_AUTO = -1,
     AVFMT_TBCF_DECODER,
@@ -3052,25 +3053,20 @@ enum AVTimebaseSource {
 };
 
 /**
- * Transfer internal timing information from one stream to another.
- *
- * This function is useful when doing stream copy.
- *
- * @param ofmt     target output format for ost
- * @param ost      output stream which needs timings copy and adjustments
- * @param ist      reference input stream to copy timings from
- * @param copy_tb  define from where the stream codec timebase needs to be imported
+ * @deprecated do not call this function
  */
+attribute_deprecated
 int avformat_transfer_internal_stream_timing_info(const AVOutputFormat *ofmt,
                                                   AVStream *ost, const AVStream *ist,
                                                   enum AVTimebaseSource copy_tb);
 
 /**
- * Get the internal codec timebase from a stream.
- *
- * @param st  input stream to extract the timebase from
+ * @deprecated do not call this function
  */
+attribute_deprecated
 AVRational av_stream_get_codec_timebase(const AVStream *st);
+#endif
+
 
 /**
  * @}
diff --git a/libavformat/internal.h b/libavformat/internal.h
index 6bad4fd119..8e8971bfeb 100644
--- a/libavformat/internal.h
+++ b/libavformat/internal.h
@@ -411,7 +411,9 @@ typedef struct FFStream {
 
     const struct AVCodecDescriptor *codec_desc;
 
+#if FF_API_INTERNAL_TIMING
     AVRational transferred_mux_tb;
+#endif
 } FFStream;
 
 static av_always_inline FFStream *ffstream(AVStream *st)
diff --git a/libavformat/options.c b/libavformat/options.c
index 60a73d79b9..2f3f8e0c96 100644
--- a/libavformat/options.c
+++ b/libavformat/options.c
@@ -317,7 +317,9 @@ AVStream *avformat_new_stream(AVFormatContext *s, const AVCodec *c)
         sti->pts_buffer[i] = AV_NOPTS_VALUE;
 
     st->sample_aspect_ratio = (AVRational) { 0, 1 };
+#if FF_API_INTERNAL_TIMING
     sti->transferred_mux_tb = (AVRational) { 0, 1 };;
+#endif
 
 #if FF_API_AVSTREAM_SIDE_DATA
     sti->inject_global_side_data = si->inject_global_side_data;
diff --git a/libavformat/version_major.h b/libavformat/version_major.h
index 44ad23c6b6..7a9b06703d 100644
--- a/libavformat/version_major.h
+++ b/libavformat/version_major.h
@@ -47,6 +47,7 @@
 #define FF_API_AVSTREAM_SIDE_DATA       (LIBAVFORMAT_VERSION_MAJOR < 62)
 
 #define FF_API_GET_DUR_ESTIMATE_METHOD  (LIBAVFORMAT_VERSION_MAJOR < 62)
+#define FF_API_INTERNAL_TIMING          (LIBAVFORMAT_VERSION_MAJOR < 62)
 
 #define FF_API_R_FRAME_RATE            1
 
-- 
2.43.0

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Re: [FFmpeg-devel] [PATCH 3/3] lavf: deprecate avformat_transfer_internal_stream_timing_info()

[James Almer]

On 7/5/2024 7:42 AM, Anton Khirnov wrote:
> And av_stream_get_codec_timebase().
> 
> They were both added for ffmpeg CLI, which no longer calls either of
> them. Furthermore the notion of "internal stream timing info" that needs
> to be transferred with a special magic API function is fundamentally
> flawed and should be removed.

LGTM
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