On Thu, Jul 23, 2015 at 06:59:54PM +0300, Ivan Uskov wrote:
> Hello Michael,
>
> Thursday, July 23, 2015, 6:29:13 PM, you wrote:
>
> >> + } else {
> >> + bs.Data = avpkt->data;
> >> + bs.DataLength = avpkt->size;
> >> + }
>
> MN> Does this mean that each packet will be memcpy-ed ?
> MN> this would slow things down
> Exactly not. Copying uses only for quite rare case when decoder does
> not consume several bytes at tail packet tail. Then these bytes copied
> into fifo. Next time these bytes usually are totally consumed with new
> packet and only reference to packets uses in general decoding.
> For several test streams I'm observing that 2-3 bytes copying appear
> only at begin of decoding, for first 5-10 frames.
> >> - do {
> >> + while (1) {
> >> ret = get_surface(avctx, q, &insurf);
> >> if (ret < 0)
> >> return ret;
> >> + do {
> >> + ret = MFXVideoDECODE_DecodeFrameAsync(q->session, avpkt->size
> >> ? &bs : NULL,
> >> + insurf, &outsurf,
> >> &sync);
> >> + if (ret != MFX_WRN_DEVICE_BUSY)
> >> + break;
> >> - ret = MFXVideoDECODE_DecodeFrameAsync(q->session, avpkt->size ?
> >> &bs : NULL,
> >> - insurf, &outsurf, &sync);
> >> - if (ret == MFX_WRN_DEVICE_BUSY)
>
> >> - av_usleep(1);
> >> + av_usleep(500);
>
> MN> looks like a unrelated change,
> MN> should be in a seperate patch with explanation
> These lines (new decoding loop) are absolutely necessary to consume all
> available data in packets. Else data not consumes and input_fifo uses all
> the time with wrong frames sequence output (duplicates and drops).
> > The reason of replacing of av_usleep(1) to av_usleep(500) is > following: I believe it is bad idea to ask hardware 1000000 times per > second if it is busy, especially in main decoding loop. > Peak qsv decoding performance is about 2000 fps when destination is GPU > memory. > For system memory the performance is less then 1000fps usually. So delay in > 500microseconds (i.e. 0.5 ms) > is much more appropriate. > I can move it to separate patch but since main decoding loop totally > re-designed possible it can be applied as? i think it should be split, as it would allow very easy regression testing with bisect, of the change in the future [...] -- Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB The worst form of inequality is to try to make unequal things equal. -- Aristotle
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