I am trying to take the audio from two mp4 files, merge them together one after the other (perhaps with some other effects such as a fade transition: not shown), and apply atempo to the result.
I am working with the current FFmpeg git master branch. I have attached an example file to reproduce the issue with: BigBuckBunny_320x180_t10.mp4 <http://www.ffmpeg-archive.org/file/t377720/BigBuckBunny_320x180_t10.mp4> . And here is the command and output: $ ffmpeg -y \ -i BigBuckBunny_320x180_t10.mp4 \ -i BigBuckBunny_320x180_t10.mp4 \ -filter_complex " aevalsrc=0:d=10[na1];[na1][1:a]concat=n=2:v=0:a=1[a1]; [0:a][a1]amix=inputs=2[mix_audio]; [mix_audio]asplit=3[mix_audio0][mix_audio1][mix_audio2]; [mix_audio0]atrim=0:5,asetpts=expr=PTS-STARTPTS[a_trim0]; [mix_audio1]atrim=5:10,asetpts=expr=PTS-STARTPTS[a_trim1]; [mix_audio2]atrim=10:20,asetpts=expr=PTS-STARTPTS[a_trim2]; [a_trim1]atempo=0.5[a_slomo1]; [a_trim0][a_slomo1][a_trim2]concat=n=3:v=0:a=1[com_a_slomo] " \ -map [com_a_slomo] \ -c:a aac \ output.m4a ffmpeg version N-87286-g6ce4a63 Copyright (c) 2000-2017 the FFmpeg developers built with gcc 4.9.2 (Debian 4.9.2-10) configuration: --prefix=/usr/local --extra-cflags=-I/usr/local/include --extra-ldflags=-L/usr/local/lib --bindir=/usr/local/bin --disable-doc --disable-static --enable-shared --disable-ffplay --extra-libs=-ldl --enable-version3 --enable-libfreetype --enable-libx264 --enable-gpl --enable-openssl --enable-nonfree --disable-debug libavutil 55. 74.100 / 55. 74.100 libavcodec 57.105.100 / 57.105.100 libavformat 57. 82.100 / 57. 82.100 libavdevice 57. 8.100 / 57. 8.100 libavfilter 6.105.100 / 6.105.100 libswscale 4. 7.103 / 4. 7.103 libswresample 2. 8.100 / 2. 8.100 libpostproc 54. 6.100 / 54. 6.100 Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'BigBuckBunny_320x180_t10.mp4': Metadata: major_brand : isom minor_version : 512 compatible_brands: isomiso2avc1mp41 title : Big Buck Bunny artist : Blender Foundation composer : Blender Foundation date : 2008 encoder : Lavf57.68.100 Duration: 00:00:10.01, start: 0.000000, bitrate: 277 kb/s Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 320x180 [SAR 1:1 DAR 16:9], 143 kb/s, 24 fps, 24 tbr, 12288 tbn, 48 tbc (default) Metadata: handler_name : VideoHandler Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 127 kb/s (default) Metadata: handler_name : SoundHandler Input #1, mov,mp4,m4a,3gp,3g2,mj2, from 'BigBuckBunny_320x180_t10.mp4': Metadata: major_brand : isom minor_version : 512 compatible_brands: isomiso2avc1mp41 title : Big Buck Bunny artist : Blender Foundation composer : Blender Foundation date : 2008 encoder : Lavf57.68.100 Duration: 00:00:10.01, start: 0.000000, bitrate: 277 kb/s Stream #1:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 320x180 [SAR 1:1 DAR 16:9], 143 kb/s, 24 fps, 24 tbr, 12288 tbn, 48 tbc (default) Metadata: handler_name : VideoHandler Stream #1:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 127 kb/s (default) Metadata: handler_name : SoundHandler Stream mapping: Stream #0:1 (aac) -> amix:input0 Stream #1:1 (aac) -> concat:in1:a0 concat -> Stream #0:0 (aac) Press [q] to stop, [?] for help Output #0, ipod, to 'output.m4a': Metadata: major_brand : isom minor_version : 512 compatible_brands: isomiso2avc1mp41 title : Big Buck Bunny artist : Blender Foundation composer : Blender Foundation date : 2008 encoder : Lavf57.82.100 Stream #0:0: Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 128 kb/s (default) Metadata: encoder : Lavc57.105.100 aac [Parsed_aevalsrc_0 @ 0x244b680] EOF timestamp not reliable [aac @ 0x2473880] Queue input is backward in time Last message repeated 1 times [ipod @ 0x2474920] Non-monotonous DTS in output stream 0:0; previous: 717824, current: -442721857768310647; changing to 717825. This may result in incorrect timestamps in the output file. [ipod @ 0x2474920] Non-monotonous DTS in output stream 0:0; previous: 717825, current: -442721857768309623; changing to 717826. This may result in incorrect timestamps in the output file. [aac @ 0x2473880] Queue input is backward in time ... <repeated combination of above two lines many times> ... size= 399kB time=00:00:14.98 bitrate= 218.0kbits/s speed=22.4x video:0kB audio:393kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 1.401464% [aac @ 0x2473880] Qavg: 1475.414 I would expect output.m4a to be 25 seconds long: 5 seconds normal playback, 10 seconds atempo=0.5, 10 seconds normal. Instead it is 15 seconds long and doesn't contain the last 10 seconds of normal playback. -- Sent from: http://www.ffmpeg-archive.org/ _______________________________________________ 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".
