[FFmpeg-soc] BFI

[Michael Niedermayer]

On Fri, Mar 21, 2008 at 05:41:56PM +0530, Sisir Koppaka wrote:
> Thanks a lot! One more question :
> The BFI file format description at the wiki (
> http://wiki.multimedia.cx/index.php?title=BFI) begins the file with byte 0
> whereas the Bethsoft VID description here (
> http://andux.svatopluk.com/docs/dfvid.html) begins with byte 1. Hence, I am
> in a bit of confusion as to how we should refer to the bytes from FFmpeg. If
> I want to seek to the video width in a BFI file for example, should I use
> url_fseek(ByteIOContextPointer,n,SEEK_SET) where n should be 43,44 or 45?

The first byte of a file, stream, ... has position 0 in libav*.


> I think SEEK_SET stands for absolute offset whereas SEEK_CUR stands for
> relative offset, but I'm not sure about them. Please correct me if I'm
> wrong.

To quote ISO/IEC 9899:1999

For a binary stream, the new position, measured in characters from the beginning of the
file, is obtained by adding offset to the position specied by whence. The specified
position is the beginning of the file if whence is SEEK_SET, the current value of the file
position indicator if SEEK_CUR, or end-of-file if SEEK_END. A binary stream need not
meaningfully support fseek calls with a whence value of SEEK_END.


[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Many that live deserve death. And some that die deserve life. Can you give
it to them? Then do not be too eager to deal out death in judgement. For
even the very wise cannot see all ends. -- Gandalf
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