[FFmpeg-devel] [PATCH][RFC] avcodec: disallow hwaccel with frame threads

[Hendrik Leppkes]

On Tue, Jan 19, 2016 at 9:13 PM, Andreas Cadhalpun
<andreas.cadhalpun at googlemail.com> wrote:
> On 22.10.2015 11:44, Hendrik Leppkes wrote:
>> On Thu, Oct 22, 2015 at 11:27 AM, Wang Bin <wbsecg1 at gmail.com> wrote:
>>> VLC is using frame threading with hwaccel
>>
>> Then they should fix their usage, its broken by design, as explained
>> in detail my post earlier in this thread.
>
> Care to provide a patch for them?


This requires deep understanding of the code in question, so nothing
anyone not familiar with the code can easily fix, so no patches for
downstreams will be provided.

>
> They now made VLC's configure error out when compiling with FFmpeg [1],
> because they currently lack time [2] to fix this the way you suggest
> and Libav doesn't return this error.
>

They don't lack time, they lack understanding of the flaws in the system.

> Thus I think it would be better to reduce this to a warning for the
> time being and maybe add a FF_API_* changing it to an error after
> the usual deprecation period.
>

I do not agree that it should be a warning. As outlined in the commit
message and this thread, there are serious flaws with frame threading
and hwaccel.

- Hendrik