[FFmpeg-devel] [PATCH v2] ffmpeg: allow full range of dts_delta_threshold

[Gyan Doshi]

For inputs from demuxers with AVFMT_TS_DISCONT flag,
the existing condition,

  delta < -1LL*dts_delta_threshold*AV_TIME_BASE

is rendered superflous due to the fixed threshold in

pkt_dts + AV_TIME_BASE/10 < FFMAX(ist->pts, ist->dts)

This prevents users from setting a high threshold to
avoid discontinuity correction due to errant timestamps.

Now, the maximum of the two thresholds is used.

fate-mpeg4-resolution-change call changed to preserve existing
timestamp correction by ffmpeg.c
---
Tested with multiple satellite MPEG-TS inputs.

 fftools/ffmpeg.c     | 2 +-
 tests/fate/mpeg4.mak | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/fftools/ffmpeg.c b/fftools/ffmpeg.c
index 0578265c1e..505fef5bdc 100644
--- a/fftools/ffmpeg.c
+++ b/fftools/ffmpeg.c
@@ -4480,7 +4480,7 @@ static int process_input(int file_index)
         if (is->iformat->flags & AVFMT_TS_DISCONT) {
             if (delta < -1LL*dts_delta_threshold*AV_TIME_BASE ||
                 delta >  1LL*dts_delta_threshold*AV_TIME_BASE ||
-                pkt_dts + AV_TIME_BASE/10 < FFMAX(ist->pts, ist->dts)) {
+                pkt_dts + FFMAX(AV_TIME_BASE/10, dts_delta_threshold*AV_TIME_BASE) < FFMAX(ist->pts, ist->dts)) {
                 ifile->ts_offset -= delta;
                 av_log(NULL, AV_LOG_DEBUG,
                        "timestamp discontinuity for stream #%d:%d "
diff --git a/tests/fate/mpeg4.mak b/tests/fate/mpeg4.mak
index ed6a2fac20..d7a9c62d7e 100644
--- a/tests/fate/mpeg4.mak
+++ b/tests/fate/mpeg4.mak
@@ -1,7 +1,7 @@
 
 MPEG4_RESOLUTION_CHANGE = down-down down-up up-down up-up
 
-fate-mpeg4-resolution-change-%: CMD = framemd5 -flags +bitexact -idct simple -i $(TARGET_SAMPLES)/mpeg4/resize_$(@:fate-mpeg4-resolution-change-%=%).h263 -sws_flags +bitexact
+fate-mpeg4-resolution-change-%: CMD = framemd5 -dts_delta_threshold 1.99 -flags +bitexact -idct simple -i $(TARGET_SAMPLES)/mpeg4/resize_$(@:fate-mpeg4-resolution-change-%=%).h263 -sws_flags +bitexact
 
 FATE_MPEG4-$(call DEMDEC, H263, H263) := $(addprefix fate-mpeg4-resolution-change-, $(MPEG4_RESOLUTION_CHANGE))
 
-- 
2.26.0