Tuesday, July 22, 2008

Good news!

Qtmux has just generated the first mov files that have audio and video that plays synchronously. MPlayer and GStreamer were able to successfully play it, VLC couldn't (not sure why, yet). Still have to test it in another players. But this is a huge step.

Now, I'll probably be working on adding flavour selection (qt, mp4 or 3gpp) using a property in the element (maybe using caps?).

Monday, July 21, 2008

Raw video into qtmux

Raw video formats were added to qtmux: 'rgb' and 'yuv' (only one 'yuv' format, but easily extensible to others). The current state is that it is possible to package video 'xor' audio into a mov file, and they are played fine.

What's keeping me busy now is to add support for synchronized audio and video. Some work has already been done, but it is still not as expected. I've re-read the spec trying to identify what info am I missing, still no clue, but I'll keep looking :)

Thursday, July 10, 2008

New audio formats for qtmux

Support for 8-bit and 16-bit pcm audio have just been added to qtmux.

I'm stepping now into video data. As it requires less knowledge about profiles and codecs, I'll start with raw rgb video. And then try to insert one format for compressed data (h263 or h264).

Inserting 8bit and 16bit pcm audio made me found a possible bug in qtdemux, already reported in bugzilla: #542410

Tuesday, July 8, 2008

The first one

I should announce that the first mp4 file has been created using qtmux (at least, the first one capable of playing nicely). It is still only able of handling mp3 audio. But that means that the underlying mp4 library reached some stable level and now the work focus should be into the qtmux element itself.

Next steps:
  1. Add another audio format support (probably raw audio)
  2. Add video support (h263? Suggestions?)
  3. Add multiplexing support (finally!)

I thought I was going to reach this goal before, but my graduation required some extra hours in the last weeks and mp4 atoms' fields given me some headache on understanding its semantics, mainly in how to define what media type (and parameters) for a track. 'qtdemux' has been a great help, it outputs some really helpful debug messages. Thanks for the guys who developed it! Great job!

Code is here: http://gforge.embedded.ufcg.edu.br/scm/?group_id=122