[FFmpeg-devel] Add Ogg Skeleton 4 support

Michael Niedermayer michaelni at gmx.at
Tue Sep 27 16:43:59 CEST 2011


On Tue, Sep 27, 2011 at 04:34:51PM +0200, Michael Niedermayer wrote:
> Hi
> 
> First, please keep ffmpeg-dev in CC
> 
> On Tue, Sep 27, 2011 at 03:50:11AM +0200, j at v2v.cc wrote:
> > Add Ogg Skeleton 4 support to the ogg demuxer. For more info on OggIndex
> > and Ogg Skeleton see https://wiki.xiph.org/Ogg_Skeleton_4
> > 
> > Addressing Diego's comments.
> 
> > If the vlc is in libav already it should be used of cause.
> 
> I dont think the ffmpeg codebase contains this and libav doesnt
> contain anything we dont so i dont think libav contains such function.
> 
> Functions doing similar things:
> ffio_read_varlen()
> ff_mp4_read_descr_len()
> bs_get_v()
> get_base128()
> read_arbitary()
> klv_decode_ber_length()
> 
> the libav people could clean this up for us and give these consistent
> names ...
> 
> also
> 
> " The variable byte encoded integers are encoded using 7 bits per byte to store the integer's bits, and the high bit is set in the last byte used to encode the integer. The bits and bytes are in little endian byte order. For example, the integer 7843, or 0001 1110 1010 0011 in binary, would be stored as two bytes: 0xBD 0x23, or 1011 1101 0010 0011 in binary. "
> 
> the specification clearly says little endian byte order and if it
> was that way get_base128() could be used.
> but then the specification contains a example that is in big endian
> order.

I meant it the other way around :)
get_base128() matches the example
The text does not

[...]

-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

The bravest are surely those who have the clearest vision
of what is before them, glory and danger alike, and yet
notwithstanding go out to meet it. -- Thucydides
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