[FFmpeg-devel] [PATCH] MLP/TrueHD decoder

Ian Caulfield ian.caulfield
Tue Oct 23 10:06:18 CEST 2007


On 22/10/2007, Michael Niedermayer <michaelni at gmx.at> wrote:
> its not the parsers job to check frames
> the only reason for a parser to not return part of the input is if it cannot
> determine the frame boundaries (for example if the frame length from some
> header is invalid/damaged)

The reasoning behind this was that MLP streams are a pain to parse -
most frames contain no sync word, just a length at the start of the
frame. There appears to be no protection against sync word emulation.
Without checking the frame parity nibble, there's no way to tell if
the stream was corrupted and the parser is now out of sync with the
stream - if this happens the parser will just return garbage frame
boundaries until the end of the stream.


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