[Libav-user] Encoding with variable frame rate

Brad O'Hearne brado at bighillsoftware.com
Wed May 22 23:22:37 CEST 2013

On May 22, 2013, at 1:29 PM, Kalileo <kalileo at universalx.net> wrote:

> Please don't complain if you don't find many willing to discuss these theories with you, most here are looking for answers or trying to help others.

I've never been wanting to "discuss theories" -- I am one of those people looking for concrete answers, with source code no less. The only reason people have conjecture about how things work is because it isn't documented anywhere, and the typical one-liner response on this mailing list frequently isn't any roadmap. Want an example? Sure -- let's take the example of another thread of mine from yesterday. Can you please produce a code example and accompanying description of exactly how to use AudioFrameQueue? That would help me tremendously. Neither resampling_audio.c, decoding_encoding.c, nor API doc to my knowledge explain this. 

> It's all open source, no secrets there, no need for theories. Everybody would appreciate that.

That comment demonstrates exactly the reason why barring a dev doing it, the probability of a solid set of FFmpeg documentation materializing is low. Any perception that because FFmpeg is open source, everything is out there is obvious and someone should be able to walk up and independently document it seems at best an extremely ambitious (and likely to be outdated by the time it is completed), if not dead wrong, perception. Audio/video encoding/decoding/streaming is a fairly challenging domain to begin with, there is a lot of code, and there are many nuances that are not clear or obvious. Those have to be known. Anyone writing documentation would have to ask many and continual detailed questions and get detailed responses, to produce good documentation. 

While I might otherwise be interested, I've done my level best to ask detailed questions just to solve a few problems, and it is pretty clear such inquisition isn't going to be received well here (and one list member's offline explanation to me of why that is makes it a virtual impossibility). That doesn't even touch on the effort to hash through conflicting responses that don't always agree with one another. So I don't see my being able to do it as a realistic possibility. 

I would however encourage the devs to do it. The best way to avoid having to have detailed discussions with anyone is for them to do it themselves. I'm sure everyone *would* appreciate that. 


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