[vlc-devel] [PATCH] Add libvlc_media_take_snapshot

[Rafaël Carré]

Le 24/04/2013 13:06, Rémi Denis-Courmont a écrit :
> On Wed, 24 Apr 2013 12:46:49 +0200, Rafaël Carré <funman at videolan.org>
> wrote:
>> Anything based on vout will suffer from poor performance as vout is
>> asynchronous of input, so it is out of the question (we will feel the
>> vout queue with several unnecessary decoded frames before we can return
>> with our snapshot picture).
> 
> The input decoder is also asynchronous with regards to the input thread.
> It gets encoded blocks from the ES output and decodes them asynchronously.
> A custom adaptor is unavoidabable to decode synchronously (like transcode
> without threading).

demuxing is less CPU intensive than decoding, thus I think plugging into
the decoder is the right thing to do (tm).

>> The idea is to decode only the necessary frames and return as soon as
>> possible to not waste time and cpu.
> 
> Again, a for more specific/customized usage of decoder_t would be
> required.
> 
>> stream_output might work but I am not sure if we can control input from
>> a stream_output (set position to middle of the file and stop input when
>> we received a frame).
> 
> input decoder, vout or sout are all equally inadequate. None of them can
> control the input.

Hm well decoder_owner_sys_t has a pointer to the input thread?