[vlc-devel] RE : [PATCH] -- still image demux

brezhoneg1 brezhoneg1 at yahoo.fr
Sun Jan 4 17:36:28 CET 2009


Please, find attached a new version of the still image generic demux
(implemented as a submodule of fake)

This set of patches is working. Yet, two enhancements could further be
done:

1- bmp and gif formats 
----------------------
These formats are wrongly taken care of by the avcodec decoder. This
decoder advertises support for both of them, but ends up with a "cannot
decode one frame" later on. On the other hand, the sdl_image perfectly
decodes them.

In other words, things like "vlc foo.bmp" or "vlc fake://
--fake-file=foo.bmp" end up with an error. Adding "--codec sdl_image"
makes them work okay.

TODO: maybe remove support of bmp and gif by avcodec or change
priorities which decoder is chosen? 


2- big images
-------------
This new image demux implementation uses the fake reference clock
without any change. Yet, for the biggest images I have, warnings like
the following occur. They are not as frequent with fake:// --fake-file=
....

     main video output warning: late picture skipped (1897382)
     [0x837f450] main decoder warning: decoder/packetizer fifo full
     (data not consumed quickly enough), resetting fifo!

The only difference I see is that the image is decoded only once in the
latter case, whereas it is decoded again and again with the new demuxer.
I didn't quite figure out all the implications regarding the pts
computation. Maybe somebody who masters the pcr issues could be of great
help to solve these warnings.

Erwan10



> -----Message d'origine-----
> De : vlc-devel-bounces at videolan.org [mailto:vlc-devel-
> bounces at videolan.org] De la part de Antoine Cellerier
> Envoyé : samedi 3 janvier 2009 23:17
> À : Mailing list for VLC media player developers
> Objet : Re: [vlc-devel] RE : [PATCH] -- still image demux
> 
> The image demux code really has lots in common with the fake://
> access_demux. Wouldn't it be possible to merge the code (provide both
> access_demux and demux capability in the fake module, kind of like
> what's done in the v4l2 module).
> 
> Other than that comment, I like the idea. It'll fix issues for a lot
of
> our users.
> 
> --
> Antoine Cellerier
> dionoea
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