Save alpha channel in video - Uncompressed only?

Jsnkc wrote on 3/3/2004, 11:57 AM

If I wanted to save a alpha channel in a video clip is the only way I can do it using a uncompressed AVI file? Any other options?

Comments

taliesin wrote on 3/3/2004, 12:02 PM

Uncompressed AVI or Quicktime. In Quicktime format some codecs can save alpha channel too. Color depth must be 32 bit or "millions +" then I think.

Marco

RBartlett wrote on 3/3/2004, 12:26 PM

Strictly speaking Microsoft made no provision for alpha channel in AVI files within the same stream. I think Adobe may have concocted that ability, not sure.

Stills frames (PNG/TGA) can also do this, within a quicktime wrapped PNG/TGA too.

A good web colleague has developed a codec for use only within Premiere/AE to store DV+alpha (4:1:1:4 NTSC, 4:2:0:4 PAL) in his own file type. Works realtime and keeps the data in its YUV format (clearly?). I don't think he has any plans to repeat his labours in Vegas, but maybe a directshow codec will come along. ( http://www.toastergarage.com ).

Why has it taken until now for anyone else to notice this?
Possibly because of the use of on-the-fly masks not held as raw data, in Vegas.