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Dans la rubrique "Champs à ajouter, cocher "Date de publication "
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Video concatenation puts sound out of sync
9 août 2019, par mmorin(Cross-posted from Video Production, where the question received no answers and may be more technical than usual video production.)
I have several
MOV
files from a DSLR camera. I concatenate them with directions from this thread :ffmpeg -safe 0 -f concat -i files_to_combine -vcodec copy -acodec copy temp.MOV
where
files_to_combine
is :file ./DSC_0013.MOV
...
file ./DSC_0019.MOVThe result has image and sound in sync for the first clip and is out of sync by fractions of a second in the second clip, and out of sync by around a second for the last clip. It is probably related to this error from the log :
[mov,mp4,m4a,3gp,3g2,mj2 @ 0x7f82dd802200] st: 0 edit list: 1 Missing key frame while searching for timestamp: 1000
[mov,mp4,m4a,3gp,3g2,mj2 @ 0x7f82dd802200] st: 0 edit list 1 Cannot find an index entry before timestamp: 1000.
[mov,mp4,m4a,3gp,3g2,mj2 @ 0x7f82dd802200] Auto-inserting h264_mp4toannexb bitstream filterHow can I trim the frames to the available sound stream, then concatenate the two videos ?
The full log from the
ffmpeg
command is :ffmpeg version 4.1.3 Copyright (c) 2000-2019 the FFmpeg developers
built with Apple LLVM version 10.0.1 (clang-1001.0.46.4)
configuration: --prefix=/usr/local/Cellar/ffmpeg/4.1.3_1 --enable-shared --enable-pthreads --enable-version3 --enable-hardcoded-tables --enable-avresample --cc=clang --host-cflags='-I/Library/Java/JavaVirtualMachines/adoptopenjdk-11.0.2.jdk/Contents/Home/include -I/Library/Java/JavaVirtualMachines/adoptopenjdk-11.0.2.jdk/Contents/Home/include/darwin' --host-ldflags= --enable-ffplay --enable-gnutls --enable-gpl --enable-libaom --enable-libbluray --enable-libmp3lame --enable-libopus --enable-librubberband --enable-libsnappy --enable-libtesseract --enable-libtheora --enable-libvorbis --enable-libvpx --enable-libx264 --enable-libx265 --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-videotoolbox --disable-libjack --disable-indev=jack --enable-libaom --enable-libsoxr
libavutil 56. 22.100 / 56. 22.100
libavcodec 58. 35.100 / 58. 35.100
libavformat 58. 20.100 / 58. 20.100
libavdevice 58. 5.100 / 58. 5.100
libavfilter 7. 40.101 / 7. 40.101
libavresample 4. 0. 0 / 4. 0. 0
libswscale 5. 3.100 / 5. 3.100
libswresample 3. 3.100 / 3. 3.100
libpostproc 55. 3.100 / 55. 3.100
[mov,mp4,m4a,3gp,3g2,mj2 @ 0x7f82dc00e000] Auto-inserting h264_mp4toannexb bitstream filter
Input #0, concat, from 'files_to_combine':
Duration: N/A, start: -0.592000, bitrate: 36888 kb/s
Stream #0:0(eng): Video: h264 (High) (avc1 / 0x31637661), yuvj420p(pc, smpte170m/bt709/bt470m), 1920x1080, 35352 kb/s, 50 fps, 50 tbr, 50k tbn, 100 tbc
Metadata:
handler_name : VideoHandler
Stream #0:1(eng): Audio: pcm_s16le (sowt / 0x74776F73), 48000 Hz, stereo, s16, 1536 kb/s
Metadata:
handler_name : SoundHandler
Output #0, mov, to 'temp.MOV':
Metadata:
encoder : Lavf58.20.100
Stream #0:0(eng): Video: h264 (High) (avc1 / 0x31637661), yuvj420p(pc, smpte170m/bt709/bt470m), 1920x1080, q=2-31, 35352 kb/s, 50 fps, 50 tbr, 50k tbn, 50k tbc
Metadata:
handler_name : VideoHandler
Stream #0:1(eng): Audio: pcm_s16le (sowt / 0x74776F73), 48000 Hz, stereo, s16, 1536 kb/s
Metadata:
handler_name : SoundHandler
Stream mapping:
Stream #0:0 -> #0:0 (copy)
Stream #0:1 -> #0:1 (copy)
Press [q] to stop, [?] for help
[mov,mp4,m4a,3gp,3g2,mj2 @ 0x7f82dd802200] st: 0 edit list: 1 Missing key frame while searching for timestamp: 1000
[mov,mp4,m4a,3gp,3g2,mj2 @ 0x7f82dd802200] st: 0 edit list 1 Cannot find an index entry before timestamp: 1000.
[mov,mp4,m4a,3gp,3g2,mj2 @ 0x7f82dd802200] Auto-inserting h264_mp4toannexb bitstream filter
frame=41886 fps=547 q=-1.0 Lsize= 3789826kB time=00:13:58.75 bitrate=37014.8kbits/s speed=10.9x
video:3631879kB audio:157123kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.021759%Update (1 July 2019)
I thought that the files had a problem at the beginning or at the end, so I
trimmed one second from each end, but it still had the sound out of sync :FILES=files_to_combine
OUTPUT=show2.MOV
rm $FILES
for i in 3 4 5 6 7 8 9; do
rm ${i}.MOV
duration=$(ffprobe -v 0 -show_entries format=duration -of compact=p=0:nk=1 DSC_001${i}.MOV)
trimmed=$(echo $duration - 1 | bc)
ffmpeg -ss 1 -t $trimmed -i DSC_001${i}.MOV -vcodec copy -acodec copy ${i}.MOV
echo file ./${i}.MOV >> $FILES
done
rm $OUTPUT
ffmpeg -safe 0 -f concat -i $FILES -vcodec copy -acodec copy $OUTPUTWhen I trim a single file near the end, the sound and video do not seem out of sync :
ffmpeg -ss 00:09:20 -t 20 -i DSC_0014.MOV -vcodec copy -acodec copy end.MOV
When I concatenate only 30 seconds from each video, the result seems OK :
FILES=files_to_combine
OUTPUT=show2.MOV
rm $FILES
for i in 3 4 5 6 7 8 9; do
rm ${i}.MOV
duration=$(ffprobe -v 0 -show_entries format=duration -of compact=p=0:nk=1 DSC_001${i}.MOV)
start=$(echo $duration - 30 | bc)
end=$(echo $duration - 1 | bc)
ffmpeg -ss $start -t $end -i DSC_001${i}.MOV -vcodec copy -acodec copy ${i}.MOV
echo file ./${i}.MOV >> $FILES
done
rm $OUTPUT
ffmpeg -safe 0 -f concat -i $FILES -vcodec copy -acodec copy $OUTPUTThis last concatenation gives this error multiple times :
[mov @ 0x7fc3c7837400] Non-monotonous DTS in output stream 0:0; previous: 9080205, current: 9080200; changing to 9080206. This may result in incorrect timestamps in the output file.
So I am guessing that the problem is small differences in timestamps that
accumulate and become more noticeable with longer durations and the
concatenation of multiple files.For reference, the DSLR that shot these clips is a Nikon D3300 and the result
offfprobe
on one of the files is :$ ffprobe DSC_0017.MOV -hide_banner
[mov,mp4,m4a,3gp,3g2,mj2 @ 0x7fab70003800] st: 0 edit list: 1 Missing key frame while searching for timestamp: 1000
[mov,mp4,m4a,3gp,3g2,mj2 @ 0x7fab70003800] st: 0 edit list 1 Cannot find an index entry before timestamp: 1000.
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'DSC_0017.MOV':
Metadata:
major_brand : qt
minor_version : 537331968
compatible_brands: qt niko
creation_time : 2019-06-12T23:52:37.000000Z
Duration: 00:09:53.58, start: 0.000000, bitrate: 36843 kb/s
Stream #0:0(eng): Video: h264 (High) (avc1 / 0x31637661), yuvj420p(pc, smpte170m/bt709/bt470m), 1920x1080, 35300 kb/s, 50 fps, 50 tbr, 50k tbn, 100 tbc (default)
Metadata:
creation_time : 2019-06-12T23:52:37.000000Z
Stream #0:1(eng): Audio: pcm_s16le (sowt / 0x74776F73), 48000 Hz, 2 channels, s16, 1536 kb/s (default)
Metadata:
creation_time : 2019-06-12T23:52:37.000000ZUpdate (9 August 2019)
I concatenated the files in iMovie and the sound and image are not as out of sync as with FFMPEG. Maybe iMovie aligns the timestamps at the end of each clip instead of concatenating the audio and image streams separately.
I ran the concatenation again with the latest
ffmpeg 4.1.4_1
on these files and others from the same camera. The audio and image are in sync in one case (the results lasts 46 minutes) out of sync in another (the result lasts 48 minutes). -
Exceeded GA’s 10M hits data limit, now what ?
21 juin 2019, par Joselyn Khor