[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

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.


> -----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
> our users.
> --
> Antoine Cellerier
> dionoea
-------------- next part --------------
A non-text attachment was scrubbed...
Name: 0004-new-generic-still-image-demuxer-implemented-as-a-su.patch
Type: application/octet-stream
Size: 7517 bytes
Desc: not available
URL: <http://mailman.videolan.org/pipermail/vlc-devel/attachments/20090104/0301d1be/attachment.obj>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: 0001-minor-changes-to-png-and-sdl_image-decoders-to-suppo.patch
Type: application/octet-stream
Size: 1816 bytes
Desc: not available
URL: <http://mailman.videolan.org/pipermail/vlc-devel/attachments/20090104/0301d1be/attachment-0001.obj>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: 0002-changes-Ext2Fourcc-into-image_Ext2Fourcc-and-exports.patch
Type: application/octet-stream
Size: 2539 bytes
Desc: not available
URL: <http://mailman.videolan.org/pipermail/vlc-devel/attachments/20090104/0301d1be/attachment-0002.obj>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: 0003-ignore-list-updated-to-allow-jpg-and-gif-images-to-b.patch
Type: application/octet-stream
Size: 1010 bytes
Desc: not available
URL: <http://mailman.videolan.org/pipermail/vlc-devel/attachments/20090104/0301d1be/attachment-0003.obj>

More information about the vlc-devel mailing list