[FFmpeg-user] filter_complex out-of-sync videos
amindfv at mailbox.org
amindfv at mailbox.org
Fri Jan 7 10:54:06 EET 2022
OS: Debian 11.2, latest ffmpeg git master.
I've got a fairly simple filtergraph that's been giving me quite a hard time in terms of starting or staying in sync. I've boiled it down to a test case with three input videos, two identical (i.e. the same file), which clearly shows at least a frame of difference: the alpha channel appears to change at least a frame before the video channel whose input is the same. This leaves very weird ghosting anytime there's significant motion in the source video.
What's going on here? Do I need to force synchronization myself? Is something else happening?
Thanks,
Tom
Full uncut console output:
$ ./ffmpeg -i <vid1.mp4> -i <vid2.mp4> -i <vid2.mp4> -filter_complex '[1:v]extractplanes=y[A], [0:v][A]alphamerge[B], [2:v][B]overlay' -q 1 -t 300 alphatest.mp4
ffmpeg version N-105195-g242ed971cb Copyright (c) 2000-2022 the FFmpeg developers
built with gcc 10 (Debian 10.2.1-6)
configuration:
libavutil 57. 18.100 / 57. 18.100
libavcodec 59. 20.100 / 59. 20.100
libavformat 59. 17.100 / 59. 17.100
libavdevice 59. 5.100 / 59. 5.100
libavfilter 8. 25.100 / 8. 25.100
libswscale 6. 5.100 / 6. 5.100
libswresample 4. 4.100 / 4. 4.100
Input #0, matroska,webm, from '<vid1.mp4>':
Metadata:
encoder : libebml v1.3.0 + libmatroska v1.4.1
creation_time : 2013-12-12T19:56:29.000000Z
Duration: 01:50:01.18, start: 0.000000, bitrate: 2206 kb/s
Stream #0:0: Video: h264 (High), yuv420p(tv, bt709/bt709/unknown, progressive), 1920x1080 [SAR 1:1 DAR 16:9], 23.98 fps, 23.98 tbr, 1k tbn (default)
Metadata:
title : <title>
Stream #0:1(eng): Audio: ac3, 48000 Hz, stereo, fltp, 96 kb/s (default)
Metadata:
title : English Audio - <title>
Input #1, matroska,webm, from <vid2.mp4>:
Metadata:
encoder : libebml v1.2.0 + libmatroska v1.1.0
creation_time : 2011-04-25T23:32:27.000000Z
Duration: 01:40:40.11, start: 0.000000, bitrate: 7289 kb/s
Chapters:
Chapter #1:0: start 0.000000, end 76.033611
Metadata:
title : Chapter 1
Chapter #1:1: start 76.033611, end 326.575567
Metadata:
title : Chapter 2
Chapter #1:2: start 326.575567, end 975.640656
Metadata:
title : Chapter 3
Chapter #1:3: start 975.640656, end 1506.128944
Metadata:
title : Chapter 4
Chapter #1:4: start 1506.128944, end 1871.368822
Metadata:
title : Chapter 5
Chapter #1:5: start 1871.368822, end 2241.613689
Metadata:
title : Chapter 6
Chapter #1:6: start 2241.613689, end 2731.352944
Metadata:
title : Chapter 7
Chapter #1:7: start 2731.352944, end 3046.250856
Metadata:
title : Chapter 8
Chapter #1:8: start 3046.250856, end 3321.609278
Metadata:
title : Chapter 9
Chapter #1:9: start 3321.609278, end 3487.399900
Metadata:
title : Chapter 10
Chapter #1:10: start 3487.399900, end 3803.841022
Metadata:
title : Chapter 11
Chapter #1:11: start 3803.841022, end 3982.060733
Metadata:
title : Chapter 12
Chapter #1:12: start 3982.060733, end 4591.919989
Metadata:
title : Chapter 13
Chapter #1:13: start 4591.919989, end 4818.646489
Metadata:
title : Chapter 14
Chapter #1:14: start 4818.646489, end 5397.474733
Metadata:
title : Chapter 15
Chapter #1:15: start 5397.474733, end 5918.161567
Metadata:
title : Chapter 16
Chapter #1:16: start 5918.161567, end 6039.491111
Metadata:
title : Chapter 17
Chapter #1:17: start 6039.491111, end 6040.106000
Metadata:
title : Chapter 18
Stream #1:0(eng): Video: h264 (High), yuv420p(tv, bt709, progressive), 1920x1080 [SAR 1:1 DAR 16:9], 23.98 fps, 23.98 tbr, 1k tbn (default)
Stream #1:1(eng): Audio: ac3, 48000 Hz, stereo, fltp, 192 kb/s (default)
Stream #1:2(eng): Audio: aac (LC), 48000 Hz, mono, fltp
Stream #1:3(eng): Subtitle: subrip (default)
Input #2, matroska,webm, from <vid2.mp4>:
Metadata:
encoder : libebml v1.2.0 + libmatroska v1.1.0
creation_time : 2011-04-25T23:32:27.000000Z
Duration: 01:40:40.11, start: 0.000000, bitrate: 7289 kb/s
Chapters:
Chapter #2:0: start 0.000000, end 76.033611
Metadata:
title : Chapter 1
Chapter #2:1: start 76.033611, end 326.575567
Metadata:
title : Chapter 2
Chapter #2:2: start 326.575567, end 975.640656
Metadata:
title : Chapter 3
Chapter #2:3: start 975.640656, end 1506.128944
Metadata:
title : Chapter 4
Chapter #2:4: start 1506.128944, end 1871.368822
Metadata:
title : Chapter 5
Chapter #2:5: start 1871.368822, end 2241.613689
Metadata:
title : Chapter 6
Chapter #2:6: start 2241.613689, end 2731.352944
Metadata:
title : Chapter 7
Chapter #2:7: start 2731.352944, end 3046.250856
Metadata:
title : Chapter 8
Chapter #2:8: start 3046.250856, end 3321.609278
Metadata:
title : Chapter 9
Chapter #2:9: start 3321.609278, end 3487.399900
Metadata:
title : Chapter 10
Chapter #2:10: start 3487.399900, end 3803.841022
Metadata:
title : Chapter 11
Chapter #2:11: start 3803.841022, end 3982.060733
Metadata:
title : Chapter 12
Chapter #2:12: start 3982.060733, end 4591.919989
Metadata:
title : Chapter 13
Chapter #2:13: start 4591.919989, end 4818.646489
Metadata:
title : Chapter 14
Chapter #2:14: start 4818.646489, end 5397.474733
Metadata:
title : Chapter 15
Chapter #2:15: start 5397.474733, end 5918.161567
Metadata:
title : Chapter 16
Chapter #2:16: start 5918.161567, end 6039.491111
Metadata:
title : Chapter 17
Chapter #2:17: start 6039.491111, end 6040.106000
Metadata:
title : Chapter 18
Stream #2:0(eng): Video: h264 (High), yuv420p(tv, bt709, progressive), 1920x1080 [SAR 1:1 DAR 16:9], 23.98 fps, 23.98 tbr, 1k tbn (default)
Stream #2:1(eng): Audio: ac3, 48000 Hz, stereo, fltp, 192 kb/s (default)
Stream #2:2(eng): Audio: aac (LC), 48000 Hz, mono, fltp
Stream #2:3(eng): Subtitle: subrip (default)
Stream mapping:
Stream #0:0 (h264) -> alphamerge (graph 0)
Stream #1:0 (h264) -> extractplanes:default (graph 0)
Stream #2:0 (h264) -> overlay (graph 0)
overlay:default (graph 0) -> Stream #0:0 (mpeg4)
Stream #0:1 -> #0:1 (ac3 (native) -> aac (native))
Press [q] to stop, [?] for help
Output #0, mp4, to '<path>/alphatest.mp4':
Metadata:
encoder : Lavf59.17.100
Chapters:
Chapter #0:0: start 0.000000, end 76.033611
Metadata:
title : Chapter 1
Chapter #0:1: start 76.033611, end 300.000000
Metadata:
title : Chapter 2
Stream #0:0: Video: mpeg4 (mp4v / 0x7634706D), yuv420p(tv, bt709, progressive), 1920x1080 [SAR 1:1 DAR 16:9], q=2-31, 200 kb/s, 23.98 fps, 14002 tbn
Metadata:
encoder : Lavc59.20.100 mpeg4
Side data:
cpb: bitrate max/min/avg: 0/0/200000 buffer size: 0 vbv_delay: N/A
Stream #0:1(eng): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 128 kb/s (default)
Metadata:
title : English Audio - <title>
encoder : Lavc59.20.100 aac
frame= 7193 fps= 55 q=1.0 Lsize= 463935kB time=00:05:00.01 bitrate=12668.1kbits/s speed=2.31x
video:457767kB audio:6016kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.032624%
[aac @ 0x55f68e9132c0] Qavg: 118.000
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