#8924 closed defect (needs_more_info)
Concat demuxer shifts video stream start time
Reported by: | Yuanjing Zhao | Owned by: | |
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Priority: | normal | Component: | undetermined |
Version: | unspecified | Keywords: | |
Cc: | Blocked By: | ||
Blocking: | Reproduced by developer: | no | |
Analyzed by developer: | no |
Description
Summary of the bug:
After processing an mp4 file with the concat demuxer and using -c copy
flag, the start_pts and start_time of the output file becomes shifted. This causes the output file to initially display a blank frame when it is first opened.
Ffmpeg version used:
ffmpeg version 4.3.1 Copyright (c) 2000-2020 the FFmpeg developers built with Apple clang version 11.0.3 (clang-1103.0.32.62) configuration: --prefix=/usr/local/Cellar/ffmpeg/4.3.1 --enable-shared --enable-pthreads --enable-version3 --enable-avresample --cc=clang --host-cflags= --host-ldflags= --enable-ffplay --enable-gnutls --enable-gpl --enable-libaom --enable-libbluray --enable-libdav1d --enable-libmp3lame --enable-libopus --enable-librav1e --enable-librubberband --enable-libsnappy --enable-libsrt --enable-libtesseract --enable-libtheora --enable-libvidstab --enable-libvorbis --enable-libvpx --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxml2 --enable-libxvid --enable-lzma --enable-libfontconfig --enable-libfreetype --enable-frei0r --enable-libass --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-librtmp --enable-libspeex --enable-libsoxr --enable-videotoolbox --disable-libjack --disable-indev=jack libavutil 56. 51.100 / 56. 51.100 libavcodec 58. 91.100 / 58. 91.100 libavformat 58. 45.100 / 58. 45.100 libavdevice 58. 10.100 / 58. 10.100 libavfilter 7. 85.100 / 7. 85.100 libavresample 4. 0. 0 / 4. 0. 0 libswscale 5. 7.100 / 5. 7.100 libswresample 3. 7.100 / 3. 7.100 libpostproc 55. 7.100 / 55. 7.100
How to reproduce:
Given an mp4 file containing video and audio stream before.mp4
Run command ffprobe before.mp4 -show_streams
, observe that video stream start_time
and start_pts
are 0.
Given a txt file concat.txt
with content:
file before.mp4
Run command ffmpeg -f concat -i concat.txt concat.mp4
Run command ffprobe concat.mp4 -show_streams
, observe that video stream start_pts
and start_time
are now non-zero.
Patches should be submitted to the ffmpeg-devel mailing list and not this bug tracker.
Attachments (5)
Change History (8)
by , 4 years ago
Attachment: | before.mp4 added |
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comment:1 by , 4 years ago
Resolution: | → needs_more_info |
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Status: | new → closed |
comment:2 by , 4 years ago
ffmpeg sets the start PTS to 0 by default, this is not related to the concat demuxer. See -copyts
.
comment:3 by , 4 years ago
Keywords: | concat demuxer start_pts start_time shift removed |
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Input file to concat demuxer