[FFmpeg-devel] [PATCH 2/3] avformat/mpegtsenc: make first_pcr sync with the first valid dts

lance.lmwang at gmail.com lance.lmwang at gmail.com
Wed Oct 21 16:40:13 EEST 2020


From: Limin Wang <lance.lmwang at gmail.com>

now first_pts assume dts will start from zero, if it's not true(copyts is enable),
too many null packet will be inserted for cbr output.

Please test with below command, you'll get huge test.ts without the patch:
./ffmpeg -y -copyts -i ../fate-suite/mpegts/loewe.ts  -c:v libx264 -x264opts \
   nal-hrd=cbr:force-cfr=1 -b:v 3500k -minrate 3500k -maxrate 3500k -bufsize \
   1000k  -c:a mp2 -muxrate 4500k  -vframes 1000 test.ts

Signed-off-by: Limin Wang <lance.lmwang at gmail.com>
---
 libavformat/mpegtsenc.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/libavformat/mpegtsenc.c b/libavformat/mpegtsenc.c
index e05d0ce..baea3b4 100644
--- a/libavformat/mpegtsenc.c
+++ b/libavformat/mpegtsenc.c
@@ -81,6 +81,7 @@ typedef struct MpegTSWrite {
     int64_t pat_period; /* PAT/PMT period in PCR time base */
     int nb_services;
     int64_t first_pcr;
+    int first_dts_check;
     int64_t next_pcr;
     int mux_rate; ///< set to 1 when VBR
     int pes_payload_size;
@@ -1136,6 +1137,7 @@ static int mpegts_init(AVFormatContext *s)
 
     if (ts->copyts < 1)
         ts->first_pcr = av_rescale(s->max_delay, PCR_TIME_BASE, AV_TIME_BASE);
+    ts->first_dts_check = 1;
 
     select_pcr_streams(s);
 
@@ -1690,6 +1692,11 @@ static int mpegts_write_packet_internal(AVFormatContext *s, AVPacket *pkt)
         stream_id = side_data[0];
 
     if (ts->copyts < 1) {
+        if (ts->first_dts_check && dts != AV_NOPTS_VALUE) {
+            ts->first_pcr += dts * 300;
+        }
+        ts->first_dts_check = 0;
+
         if (pts != AV_NOPTS_VALUE)
             pts += delay;
         if (dts != AV_NOPTS_VALUE)
-- 
1.8.3.1



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