Hi On Sat, May 14, 2022 at 7:02 PM Roger <[email protected]> wrote:
> > What are the differences when specifying the format/contain as MP4 or > H264? MP4 can contain a variety of streams, including h264. If you specify h264, you just have a raw h264 video stream, that's it. > > Are there any differences, when additionally specifying the video and > audio > codecs? > > $ ffmpeg-formats |grep mp4 > D mov,mp4,m4a,3gp,3g2,mj2 QuickTime / MOV > E mp4 MP4 (MPEG-4 Part 14) > > MPEG-4 Part 14 > https://en.wikipedia.org/wiki/MPEG-4_Part_14 > Laste published release: January 2020; 2 years ago > > $ ffmpeg-formats |grep h264 > DE h264 raw H.264 video > > Advanced Video Coding > https://en.wikipedia.org/wiki/Advanced_Video_Coding > Last published version: 22 August 2021 > > > So what are the differences between the following? > Have you actually tested these out? > > $ ffmpeg -i video-in.ts -f mp4 -vcodec libx264 -preset ultrafast > -profile:v main -acodec aac video-out.mp4 > Assuming your input has audio streams, this will just encode your input to h264 video with aac audio in an mp4 container. > > $ ffmpeg -i video-in.ts -f h264 -vcodec libx264 -preset ultrafast > -profile:v main -acodec aac video-out.mp4 > This will take your input which may or may not have audio, and turn it into a raw h264 stream, which you have then confusingly named the output with a .mp4 extension, but something like .h264 might make a bit more sense, as I've seen raw h264 streams appear like this. I am not an expert on raw h264 streams, so I might be very wrong about all this, but I tested with the following: ffmpeg -f lavfi -i sine -f lavfi -i testsrc -f mp4 -vcodec libx264 -pix_fmt yuv420p -preset ultrafast -profile:v main -acodec aac -t 4 mp4.mp4 and ffmpeg -f lavfi -i sine -f lavfi -i testsrc -f h264 -vcodec libx264 -pix_fmt yuv420p -preset ultrafast -profile:v main -acodec aac -t 4 h264.mp4 The former had the audio stream, the latter did not. Best, Kieran O'Leary National Library of Ireland > > > Roger > > _______________________________________________ > ffmpeg-user mailing list > [email protected] > https://ffmpeg.org/mailman/listinfo/ffmpeg-user > > To unsubscribe, visit link above, or email > [email protected] with subject "unsubscribe". > _______________________________________________ ffmpeg-user mailing list [email protected] https://ffmpeg.org/mailman/listinfo/ffmpeg-user To unsubscribe, visit link above, or email [email protected] with subject "unsubscribe".
