[FFmpeg-devel] [libav-devel] [PATCH 2/2] lavf: move internal fields from public to internal context

Andreas Cadhalpun andreas.cadhalpun at googlemail.com
Wed Mar 4 21:49:17 CET 2015

On 04.03.2015 21:14, wm4 wrote:
> On Wed, 4 Mar 2015 21:05:04 +0100
> Hendrik Leppkes <h.leppkes at gmail.com> wrote:
>> On Wed, Mar 4, 2015 at 8:59 PM, wm4 <nfxjfg at googlemail.com> wrote:
>>> On Wed, 04 Mar 2015 20:21:26 +0100
>>> Andreas Cadhalpun <andreas.cadhalpun at googlemail.com> wrote:
>>>> Unfortunately XBMC is using these semi-private fields, so it gets broken by this
>>>> change. Therefore I think it would be better to postpone this until after a
>>>> SOVERSION bump.
>>>> Looking a bit closer at the source [1], it seems XBMC uses this only to provide
>>>> a ff_read_frame_flush equivalent called xbmc_read_frame_flush.
>>>> To avoid having to do that in XBMC I suggest to rename ff_read_frame_flush back
>>>> to av_read_frame_flush and add it to the public API. Thoughts?
>>> I don't think this is a valid excuse. Tell XBMC to fix their code.

It's no excuse, but a problem that has to be solved one way or another.
And making ff_read_frame_flush public is the easiest fix, isn't it?

>> I agree. API explicitly marked as private needs to be possible to be
>> changed at any time, or our development is severly impaired.

That's true, but it's not entirely XBMC's fault, since the function was
called av_read_frame_flush first (as if it was public) and only later
renamed. (They shouldn't have worked around that by using other private
functions, though.)

> This may be in conflict with the FFmpeg philosophy /sarcasm.
>> Doesn't XBMC use a private copy of ffmepg anyway? They can adapt by
>> the time they update it.
> Yep.

At least in Debian it luckily doesn't use that, but instead the shared

>> Also, instead of just making some function public, maybe someone
>> should bother to explain why we would need it?
> Flushing the demuxer can actually be useful. I even sent a patch once,
> but apparently it went nowhere. It still can be simulated with a byte
> seek to the current position, though.

So what do you think about resurrecting this patch (add avformat_flush)?
It seems to have only stalled on the associated documentation and the
XBMC developers are apparently not the only ones who would find it useful.

Best regards,

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