[vlc-devel] [PATCH 3/4] avformat mux: Mark keyframe blocks as such.

Steinar H. Gunderson sgunderson at bigfoot.com
Sun Aug 18 18:50:29 CEST 2013

On Sun, Aug 18, 2013 at 06:37:58PM +0200, Luca Barbato wrote:
>> Some browsers, such as Firefox, are very picky about WebM streams needing to
>> start with a keyframe. To be able to handle this correctly when streaming,
>> the avformat mux needs to mark keyframe-containing blocks (or clusters, in
>> Matroska terminology) as such even after they have been muxed. The next patch
>> in the series will make httpd actually care about this flag.
> I'd advise you to keep around a fake keyframe and interpose it before
> serving the real content.

I'm not sure if I understand. First of all: Should I do this just at the
beginning of the stream? What would be the advantage -- to see if the output
is delayed or not?

Also, where would I get such a fake keyframe from? Does this mean that the
mux needs to know what a VP8 keyframe would look like? Would it mean that
there's a junk keyframe in the output stream?

/* Steinar */
Homepage: http://www.sesse.net/

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