[XviD-devel] illegal MPEG-4 Bitstream Syntax / RAW YUV input swaped

Marco Al xvid-devel@xvid.org
Fri, 3 Jan 2003 23:29:53 +0100


Andreas Dehnhardt wrote:

> The decoding failed at the second I-VOP, it complained about an illegal
> VOP_START_CODE while parsing the bitstream. This error is caused by
> FrameCodeI() in "encoder.c". There is a new VO/VOL-Header inserted into the
> bitstream (BitstreamWriteVolHeader()) for every new I-VOP. According to
> the MPEG-4 standard, this structure is illegal. The VO/VOL-Header is only
> allowed at the start of the sequence. The VOPs (in our case, a Frame is
> equal to a VOP) are instances of one VideoObject (VO) at a given time.
> VideoObjectLayers (VOLs) are used for object based temporal and spatial
> scalability (not included in the simple profile of MPEG-4). We only have
> one VO and one VOL, so we cannot include more than one VO/VOL-Header.

What about :

"The Visual Object Sequence Header, the Visual Object Header and the Video
Object Layer Header may be repeated in a single visual bitstream. Repeating
these headers enables random access into the visual bitstream and recovery of
these headers when the original headers are corrupted by errors. This header
repetition is used only when visual_object_type in the Visual Object Header
indicates that visual object type is video."

? :)

Marco