On Sep 13, 2017 4:32 AM, "Jonathan Girven" <jonathan.gir...@trickbook.com> wrote:
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 I haven't tested such use case, but I can tell you atempo also changes output pts (computes it based on the number of samples output so far). So shouldn't mix_audio2 asetpts expression reference the output of atempo for STARTPTS? Pavel _______________________________________________ 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".
