[vlc-devel] [RFC] access: also use prefetch cache for block accesses

Rémi Denis-Courmont remi at remlab.net
Fri Mar 18 19:34:37 CET 2016

Le 2016-03-18 12:19, Thomas Guillem a écrit :
> On Thu, Mar 17, 2016, at 18:16, Rémi Denis-Courmont wrote:
>> Le 2016-03-17 12:26, Thomas Guillem a écrit :
>> > The prefetch cache is only used for non-fast-seekable accesses,
>> > (mainly network
>> > accesses). One more memcpy is insignificant for network accesses 
>> that
>> > are
>> > cached on a tmp file.
>> Maybe, but there is still the problem of block granularity, 
>> especially
>> for truly block-based inputs.
> I don't think I understand the problem, do you have an example of 
> such
> input ?

If you have one or more blocks of X bytes in the queue between access 
and stream filter, and the stream filter asks for Y > X bytes, then the 
X bytes are not dequeued. They will only be dequeued once either EOS is 
reached or the missing Y - X bytes arrive. Either way, it can cause 
buffer timing problems.

Rémi Denis-Courmont

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