[vlc-devel] [PATCH] Add libvlc_media_take_snapshot

Rémi Denis-Courmont remi at remlab.net
Wed Apr 24 13:06:25 CEST 2013

On Wed, 24 Apr 2013 12:46:49 +0200, Rafaël Carré <funman at videolan.org>
> 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).

> 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

> 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.

Rémi Denis-Courmont
Sent from my collocated server

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