[MPlayer-users] Bugs in MPEG-2 pack header and system header

Jimmy Blair blueskyjb at verizon.net
Tue Jan 27 23:02:18 CET 2004

I ran a VOB file through an MPEG-2 stream analyzer and found some errors 
in the headers, specifically the pack header and the packet header.  The 
packet header bug is that the stuffing bytes appear in the wrong place. 
    They should be just before the payload, not in the middle of the 
header. Note: the stuffing is correct for MPEG-1.  If you play back the 
VOB in RealPlayer, you'll see the effect -- a frame will be dropped and 
the video jerks.

There are 2 pack header bugs for MPEG-2.  One is an extraneous marker 
bit following the MPEG-2 clock extension field.  The other is a missing 
marker bit right before the reserved field.  These bugs cause no 
playback error; however, they cause an MPEG-2 stream analyzer to 
complain that the mux rate exceeds the rate bound in the system headers.

If anybody is interested, let me know and I'll send you a patchfile for 
libavformat/mpeg.c.  Maybe someone from the developer's list??


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