[FFmpeg-devel] [PATCH] RTP depacketizer for AMR

Michael Niedermayer michaelni
Wed Jan 27 17:46:47 CET 2010

On Wed, Jan 27, 2010 at 05:15:50PM +0200, Martin Storsj? wrote:
> Hi,
> On Wed, 27 Jan 2010, Michael Niedermayer wrote:
> > > I also tried returning all frames at once, but ffmpeg.c gives the 
> > > "Multiple frames in a packet from stream" error message (but works fine 
> > > except for that).
> > 
> > is there a meassureable difference in speed between returning all and
> > spliting? Spliting is preferred but if there are speed advantages then
> > we might think about detecting the cases where spliting is unneeded and
> > avoid it. (its unneeded when decoding, needed when doing stream copy)
> Splitting it within the RTP depacketizer needs one extra memcpy compared 
> to returning all data at once, but I guess the same copy would have to be 
> done in a parser instead (for the stream copy case) if we don't split them 
> here.

so why does it need a copy?

> As for the speed difference, I don't really think it's measurable. The 
> data amount for AMR is very low anyway (around 1,6 KB/s), so one extra 
> memcpy of that amount isn't bad. And splitting may have to be done at some 
> point anyway.

have you considered a little battery powered cpu in something like a phone?

Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Many things microsoft did are stupid, but not doing something just because
microsoft did it is even more stupid. If everything ms did were stupid they
would be bankrupt already.
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