[FFmpeg-devel] [PATCH 01/15] libavformat: Increase probe buffer to 16MB

[Tomas Härdin]

ons 2024-11-13 klockan 14:40 +0100 skrev Michael Niedermayer:
> Hi
> 
> On Tue, Oct 29, 2024 at 03:44:30PM +0100, Tomas Härdin wrote:
> > Needs a sample. An option or setting for probe size might be a good
> > idea
> > 
> > Spotify comments
> > ----------------
> > In mp3 files, id3v2 tag with huge cover art causes the probe code
> > to
> > not identify valid mp3 files as mp3. Increase default buffer so
> > that
> > probe can see mp3 frames.
> 
> Does this work if its limited to cases where huge ID3 is detected ?
> or we could seek forward over the ID3 detect format and then go
> back and do the normal open code

Can't we have it just rely on there being an ID3 header? Are there
counterexamples?

The probe logic (av_probe_input_format3()) has special logic for ID3
headers, skipping past them to allow the normal MP3 probing to inspect
the essence data following the header. This only works if it's given
enough probe data

Seeking can be expensive, especially when the data is served over HTTP

/Tomas