Position of Images and Audio in a Video File
Greetings, I have wondered how the Images and the Audio is placed in a Video File We speak of them as Tracks but I am trying to learn how it is placed binarily one after the other. It is after all just a binary list of numbers or codes. I download files which are in dash format from Youtube using youtube-dl. And it appears that the Video is separately downloaded and Audio separately After that the 2 files are merged together into one file. I would much appreciate having a pointer in the directions where I could read more about this. Regards Mettavihari [download] Wi-Fi World Congress Europe Day 1-551888518.fdash-fastly_skyfire_sep-video-59b7287b.mp4 has already been downloaded [download] 100% of 884.25MiB [dashsegments] Total fragments: 1906 [download] Destination: Wi-Fi World Congress Europe Day 1-551888518.fdash-fastly_skyfire_sep-audio-0c5aa284.m4a [download] 100% of 351.41MiB in 28:00 [ffmpeg] Merging formats into "Wi-Fi World Congress Europe Day 1-551888518.mp4" Deleting original file Wi-Fi World Congress Europe Day 1-551888518.fdash-fastly_skyfire_sep-video-59b7287b.mp4 (pass -k to keep) Deleting original file Wi-Fi World Congress Europe Day 1-551888518.fdash-fastly_skyfire_sep-audio-0c5aa284.m4a (pass -k to keep) -- Streaming video from http://learntv.lk
Hi, Due to playout requirements (sequential access) it is typically made available as interleaved blocks. But it can also be completely independent tracks, and synchronised by the meta description for example with SMIL. You might want to review a well documented container format such as Matroska https://matroska.org/index.html or OGG https://xiph.org/ogg/doc/oggstream.html -- Stefan
Greetings Stefan, Thank you for the links. They are very useful. Mettavihari On Sun, May 23, 2021 at 6:34 PM Stefan de Konink <stefan@konink.de> wrote:
Hi,
Due to playout requirements (sequential access) it is typically made available as interleaved blocks. But it can also be completely independent tracks, and synchronised by the meta description for example with SMIL.
You might want to review a well documented container format such as Matroska https://matroska.org/index.html or OGG https://xiph.org/ogg/doc/oggstream.html
-- Stefan _______________________________________________ ffmpeg-user mailing list ffmpeg-user@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-user
To unsubscribe, visit link above, or email ffmpeg-user-request@ffmpeg.org with subject "unsubscribe".
-- Streaming video from http://learntv.lk
participants (2)
-
Mettavihari D -
Stefan de Konink