[FFmpeg-devel] GSoC Qual VQA v3 : patch updated

Michael Niedermayer michaelni
Mon Apr 13 20:14:43 CEST 2009


On Mon, Apr 13, 2009 at 01:39:36PM -0400, The Deep Explorer wrote:
> Hi,
>    I have checked and removed the cosmetic changes.
> 
> Thanks for the feedback Diego, when I was trying to revert, I could
> understand how painful the cosmetic changes can be. Lesson learnt.
> 
> I hope this is a much better patch.
> 

> Hopefully, now I will get some feedback on the algorithm. I definitely
> need the vector indexing mechanism for V3. Please anyone.

I see nothing unclear in the desription of the algo on the wiki.


[...]
> +static void vqa_decode_vptr(const unsigned char *src, int src_size,
> +    unsigned char *dest, int dest_size)
> +{
> +    int src_index = 0;
> +    int dest_index = 0;
> +    short int code_buf = 0;
> +    short int code = 0;
> +    int block_no = 0;
> +    int count = 0;
> +    int index = 0;
> +
> +    while (src_index < src_size) {
> +        memcpy(&code_buf, &src[src_index], 2);
> +        code = code_buf >> 13;

this code makes no sense.


> +        code = code & 0x0007;
> +
> +        switch (code) {
> +
> +        case 0:
> +            count = code_buf & 0x1ff;
> +            dest_index += count;
> +            break;
> +        case 1:
> +            block_no = code_buf & 0x1ff;
> +            count = (((code_buf / 256) & 0x1f) + 1) * 2;
> +            for (index = 0; index < count; index++)
> +                dest[dest_index + index] = block_no;
> +            dest_index += index;

this as well makes no sense, and i guess i could repeat that comment
a few more times

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

Everything should be made as simple as possible, but not simpler.
-- Albert Einstein
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