Re: [mpeg2-dev] Buffer Queues and libmpeg2

[Michel L. <wa...@zo...>]

On Wed, Nov 19, 2008 at 09:29:07AM +0100, Martin Hering wrote:
> I am currently experimenting with libmpeg2 for use in a video player
> project. I am currently using it straight out of the box and it works
> fine. When the decoder is finished and gives me back a display picture I
> just copy the display_fbuf to another buffer which can be queued for
> later playback. However this method is not very efficient since copying
> a block of memory as huge as a picture always imposes the burden of a
> big system load. I was wondering if I could simply switch the buffer
> pointers, say I give display_fbuf->buf[...] the pointers to the memory
> region that I would normaly queue up and queue up the display_fbuf->buf
> instead. However this is currently not possible due to being
> display_fbuf defined as const. I removed the const for testing only, but
> it seems that this is not a valid method, since my app crashes at some
> point. My question now is, is there a legal method of switching buffers
> or does anybody have a better solution?

Look at doc/sample5.c and doc/sample6.c, they do what you want, with the
app picking a new buffer at every STATE_PICTURE state and passing it to
the decoder.

-- 
Michel "Walken" Lespinasse
A program is never fully debugged until the last user dies.