Vorbis dev - Dec 2007 - Query in codebook decoding

Hello Monty,

Sorry for the wrong subject title last time. A little more clarification
needed.

When reading bit-by-bit, there is no MSb/LSb, just 'first bit' and
'last bit'.  The Huffman tree is traversed from 'first bit' to
last
bit'.  This is a conceptual layer above the bitpacker; all you need to
know is what order the bits come out, which happens to be LSb-first.

For ex. say we have the following codewords in the codebook

entry 0: codeword0 - 00
entry 2: codeword1 - 0111
entry 6: codeword2 - 111
entry 7: codeword3 - 10

Now in the bitstream if there is [codeword0] followed by [codeword3]
followed by [codeword1], then will bitstream be

 msb             lsb
.... 0111 10 00            or will it be

 msb             lsb
.... 1110 01 00

If it is the second case, then we can traverse the tree as and when we get
the bits from from the bitstream. But if it is the first case, then how do
we do the decoding ?

Regards,
Sanjay
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I think I got the answer in the spec. The bit stream must be

  msb             lsb
.... 1110 01 00

Thanks anyway,





On Dec 12, 2007 11:42 AM, Sanjay Rajashekar <sanjay.rajashekar@gmail.com>
wrote:
> Hello Monty,
>
> Sorry for the wrong subject title last time. A little more clarification
> needed.
>
> When reading bit-by-bit, there is no MSb/LSb, just 'first bit' and
> 'last bit'.  The Huffman tree is traversed from 'first bit'
to last
> bit'.  This is a conceptual layer above the bitpacker; all you need to
> know is what order the bits come out, which happens to be LSb-first.
>
> For ex. say we have the following codewords in the codebook
>
> entry 0: codeword0 - 00
> entry 2: codeword1 - 0111
> entry 6: codeword2 - 111
> entry 7: codeword3 - 10
>
> Now in the bitstream if there is [codeword0] followed by [codeword3]
> followed by [codeword1], then will bitstream be
>
>  msb             lsb
> .... 0111 10 00            or will it be
>
>  msb             lsb
> .... 1110 01 00
>
> If it is the second case, then we can traverse the tree as and when we get
> the bits from from the bitstream. But if it is the first case, then how do
> we do the decoding ?
>
> Regards,
> Sanjay
>
>
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