[FFmpeg-devel] rough PATCH: reducing the memory copies

[Michael Niedermayer]

Hi

On Mon, Jun 25, 2007 at 08:01:15PM -0400, mmh wrote:
Content-Description: message body text
> 
> This saves me about 50MIPS + reduce cache stress, by elliminating this
> memory copy, which I guess happens later anyways again.
> 
> I know that I need to creat a new function in utils.c for this like
> av_new_packet probably av_ref_packet which does the work in the if variant.
> 
> What are the problems with this and, other ideas that comes to mind?

there probably wont be any problems, it should work fine though
as you suspected it will sometimes tough not always cause a memcpy()
to be done later ...


[...]
> -
> +    PROF_BEGIN();

this doesnt belong in here, the code is messy enough as is


>      ptr = s->video_buf + s->gb_buffers.offsets[s->gb_frame];
> -    memcpy(buf, ptr, s->frame_size);
>  
> +    if (s->gb_buffers.frames > 1) {
> +        av_free (pkt->data);

alloc+free is not ok, dont malloc()


> +        pkt->destruct= av_destruct_packet_nofree;
> +        pkt->data = ptr;
> +	pkt->size = s->frame_size;

tab


[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Why not whip the teacher when the pupil misbehaves? -- Diogenes of Sinope
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