Hello I'm trying to use FFmpeg for a relatively simple task of trimming a 24fps .MOV file to make a shorter .MOV.
The source has been exported from Avid Media Composer. Programatically I know the in point and out point to trim to, and the arguments I'm passing to FFmpeg look like they ought to be correct (I think?). However, when I perform the trim and then line up the source with the trimmed version in Adobe Premiere, I'm finding that: - The audio is perfectly in sync to the source video, but the video track is 2 frames early- so where I would expect to see frame 100, instead, I'm seeing frame 102 - The trimmed .MOV is 1 frame too short for the -t duration that I gave I'm trying to set this up for long episodes with lots of shots in, where the automation will be helpful, but it's for animation purposes so video frame accuracy is going to be essential. For copyright reasons I can't share that footage so I've done some tests using homemade footage instead. If anyone's interested, you can find both a copy of the source video and the inaccurately-trimmed output video here: http://www.twentypenguins.co.uk/misc/ffmpeg_tests/ The arguments I'm passing and the FFmpeg output I'm getting are pasted below. I've edited out the filepaths for privacy but they're all valid and I'm confident that's not the problem. Is there anyone who might be able to have a look at this and spot why FFmpeg appears to be generating a file where the video and audio aren't currently in sync? Any assistance would be greatly appreciated. Stuart Arguments: -i "OutputTests_24p_v2.mov" -ss 00:00:04.041 -t 00:00:02.720 -r 24 "AR0000003_H264-FF_v20.mov" FFmpeg output: ffmpeg version N-89369-g5a93a85fd0 Copyright (c) 2000-2017 the FFmpeg developers built with gcc 7.2.0 (GCC) configuration: --enable-gpl --enable-version3 --enable-sdl2 --enable-bzlib --enable-fontconfig --enable-gnutls --enable-iconv --enable-libass --enable-libbluray --enable-libfreetype --enable-libmp3lame --enable-libopenjpeg --enable-libopus --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libtheora --enable-libtwolame --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxml2 --enable-libzimg --enable-lzma --enable-zlib --enable-gmp --enable-libvidstab --enable-libvorbis --enable-cuda --enable-cuvid --enable-d3d11va --enable-nvenc --enable-dxva2 --enable-avisynth --enable-libmfx libavutil 56. 4.100 / 56. 4.100 libavcodec 58. 6.102 / 58. 6.102 libavformat 58. 2.103 / 58. 2.103 libavdevice 58. 0.100 / 58. 0.100 libavfilter 7. 6.100 / 7. 6.100 libswscale 5. 0.101 / 5. 0.101 libswresample 3. 0.101 / 3. 0.101 libpostproc 55. 0.100 / 55. 0.100 Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'OutputTests_24p_v2.mov': Metadata: creation_time : 2017-12-23T10:12:48.000000Z timecode : 01:00:00:00 Duration: 00:00:09.50, start: 0.000000, bitrate: 3233 kb/s Stream #0:0(eng): Audio: pcm_s16be (twos / 0x736F7774), 44100 Hz, mono, s16, 705 kb/s (default) Metadata: creation_time : 2017-12-23T10:12:48.000000Z handler_name : Apple Alias Data Handler Stream #0:1(eng): Video: h264 (Main) (avc1 / 0x31637661), yuv420p(tv, smpte170m/smpte170m/bt709), 640x360, 2303 kb/s, 24 fps, 24 tbr, 24k tbn, 48k tbc (default) Metadata: creation_time : 2017-12-23T10:12:48.000000Z handler_name : Apple Alias Data Handler encoder : H.264 Stream #0:2(eng): Data: none (tmcd / 0x64636D74), 0 kb/s (default) Metadata: creation_time : 2017-12-23T10:12:56.000000Z handler_name : Apple Alias Data Handler timecode : 01:00:00:00 Stream mapping: Stream #0:1 -> #0:0 (h264 (native) -> h264 (libx264)) Stream #0:0 -> #0:1 (pcm_s16be (native) -> aac (native)) Press [q] to stop, [?] for help [libx264 @ 000001d16eda0d00] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX [libx264 @ 000001d16eda0d00] profile High, level 3.0 [libx264 @ 000001d16eda0d00] 264 - core 152 r2851 ba24899 - H.264/MPEG-4 AVC codec - Copyleft 2003-2017 - http://www.videolan.org/x264.html - options: cabac=1 ref=3 deblock=1:0:0 analyse=0x3:0x113 me=hex subme=7 psy=1 psy_rd=1.00:0.00 mixed_ref=1 me_range=16 chroma_me=1 trellis=1 8x8dct=1 cqm=0 deadzone=21,11 fast_pskip=1 chroma_qp_offset=-2 threads=6 lookahead_threads=1 sliced_threads=0 nr=0 decimate=1 interlaced=0 bluray_compat=0 constrained_intra=0 bframes=3 b_pyramid=2 b_adapt=1 b_bias=0 direct=1 weightb=1 open_gop=0 weightp=2 keyint=250 keyint_min=24 scenecut=40 intra_refresh=0 rc_lookahead=40 rc=crf mbtree=1 crf=23.0 qcomp=0.60 qpmin=0 qpmax=69 qpstep=4 ip_ratio=1.40 aq=1:1.00 Output #0, mov, to 'AR0000003_H264-FF_v20.mov': Metadata: timecode : 01:00:00:00 encoder : Lavf58.2.103 Stream #0:0(eng): Video: h264 (libx264) (avc1 / 0x31637661), yuv420p, 640x360, q=-1--1, 24 fps, 12288 tbn, 24 tbc (default) Metadata: creation_time : 2017-12-23T10:12:48.000000Z handler_name : Apple Alias Data Handler encoder : Lavc58.6.102 libx264 Side data: cpb: bitrate max/min/avg: 0/0/0 buffer size: 0 vbv_delay: -1 Stream #0:1(eng): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, mono, fltp, 69 kb/s (default) Metadata: creation_time : 2017-12-23T10:12:48.000000Z handler_name : Apple Alias Data Handler encoder : Lavc58.6.102 aac frame= 66 fps=0.0 q=-1.0 Lsize= 246kB time=00:00:02.73 bitrate= 735.6kbits/s speed=3.67x video:219kB audio:23kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 1.684352% [libx264 @ 000001d16eda0d00] frame I:1 Avg QP:24.89 size: 8737 [libx264 @ 000001d16eda0d00] frame P:19 Avg QP:23.00 size: 4080 [libx264 @ 000001d16eda0d00] frame B:46 Avg QP:23.71 size: 2978 [libx264 @ 000001d16eda0d00] consecutive B-frames: 1.5% 12.1% 13.6% 72.7% [libx264 @ 000001d16eda0d00] mb I I16..4: 28.5% 48.8% 22.7% [libx264 @ 000001d16eda0d00] mb P I16..4: 35.2% 40.4% 4.5% P16..4: 9.1% 2.7% 1.6% 0.0% 0.0% skip: 6.6% [libx264 @ 000001d16eda0d00] mb B I16..4: 15.2% 17.9% 1.4% B16..8: 30.4% 4.9% 1.0% direct: 4.7% skip:24.5% L0:58.2% L1:38.5% BI: 3.3% [libx264 @ 000001d16eda0d00] 8x8 transform intra:51.1% inter:83.2% [libx264 @ 000001d16eda0d00] coded y,uvDC,uvAC intra: 27.8% 53.2% 2.7% inter: 17.0% 34.5% 0.3% [libx264 @ 000001d16eda0d00] i16 v,h,dc,p: 28% 26% 20% 26% [libx264 @ 000001d16eda0d00] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu: 27% 22% 33% 4% 4% 2% 4% 3% 2% [libx264 @ 000001d16eda0d00] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 26% 22% 29% 4% 5% 3% 6% 3% 2% [libx264 @ 000001d16eda0d00] i8c dc,h,v,p: 49% 26% 22% 3% [libx264 @ 000001d16eda0d00] Weighted P-Frames: Y:0.0% UV:0.0% [libx264 @ 000001d16eda0d00] ref P L0: 59.9% 8.7% 18.2% 13.1% [libx264 @ 000001d16eda0d00] ref B L0: 87.4% 9.6% 3.0% [libx264 @ 000001d16eda0d00] ref B L1: 95.4% 4.6% [libx264 @ 000001d16eda0d00] kb/s:649.38 [aac @ 000001d16edb4cc0] Qavg: 670.924 -- Stuart Bruce - stu...@stuartbruce.co.uk - www.stuartbruce.co.uk _______________________________________________ ffmpeg-user mailing list ffmpeg-user@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-user To unsubscribe, visit link above, or email ffmpeg-user-requ...@ffmpeg.org with subject "unsubscribe".
