[FFmpeg-devel] [RFC] per format probe buffer sizes

Benjamin Larsson banan
Tue Apr 15 18:48:43 CEST 2008

Benjamin Larsson wrote:
> Hello, while trying to work out how to get dts in wav detection to work 
> properly I found out that there was a problem with the size of the probe 
> buffer. Right now it starts from 2048 and increases the size until a 
> format is detected. And when the wav format is used with a command line 
> like "ffmpeg -i dts.wav test.wav" the format is detected in the first 
> try. And reliable dts detection in a test file I had will need more. It 
> found the first SYNC word after 3072 bytes. So for this to work we need 
> to increase this buffer, one could either do it globally or just for the 
> needed format. Before the actual probing that finds the wav format 
> (utils.c:447) there is another probe (utils:433). My suggestion is that 
> we add a flag and size parameter to the format struct and let this probe 
> call fetch this value so it can be used later in the real 
> probe(utils.c:447). This way we can add per format probe sizes which 
> might useful.
> So what do you think of this idea ?
> MvH
> Benjamin Larsson

Here is a patch describing the idea, for it to work we would need to re 
add  format extensions for the formats which support/need custom probe size.

Benjamin Larsson
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