[meta-freescale] imx-vpu-hantro: broken A/V sync with VP8 playback

Otavio Salvador otavio.salvador at ossystems.com.br
Thu Dec 13 05:48:47 PST 2018


Hello Carlos,

On Sat, Dec 8, 2018 at 8:43 AM Carlos Rafael Giani <crg7475 at mailbox.org> wrote:
> I recently noticed that VP8 playback does not work correctly with
> imx-vpu-hantro . If a VP8 stream contains alternate reference (altref)
> frames, then imx-vpu-hantro decodes them correctly, but does not inform
> about the fact that they are altref frames. This is a problem, because
> altref frames are supposed to be decoded, and NOT shown. In particular,
> timestamps should not be increased because of a decoded altref frame.
> They essentially are for internal use only.
>
> However, because the callers do not know that a frame is an altref one,
> they don't skip them like they should. As a result, A/V sync gradually
> gets worse over time.
>
> Is there any newer imx-vpu-hantro version that fixes this? The necessary
> fields are already there. Specifically, there's isGoldenOrAlternate in
> the FRAME struct in openmax_il/source/decoder/codec.h . However, it is
> never set to TRUE . I did some digging, and the only part that sets any
> flag like that is in vp8decmcapi.c (which is not used), and even then,
> this concerns itself only with golden frames, not altref ones.

Adding Carol to Cc...

-- 
Otavio Salvador                             O.S. Systems
http://www.ossystems.com.br        http://code.ossystems.com.br
Mobile: +55 (53) 9 9981-7854          Mobile: +1 (347) 903-9750


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