[FFmpeg-devel] [PATCH] Add DPX decoder rev-15

[Michael Niedermayer]

On Wed, Jun 03, 2009 at 11:56:44AM +0200, Jimmy Christensen wrote:
> On 2009-06-03 11:33, Michael Niedermayer wrote:
>> On Wed, Jun 03, 2009 at 09:16:39AM +0200, Jimmy Christensen wrote:
>>> On 2009-06-02 22:21, Michael Niedermayer wrote:
>>>> On Tue, Jun 02, 2009 at 10:18:02AM +0200, Jimmy Christensen wrote:
>>>> [...]
>>>>> +typedef struct DPXContext {
>>>>> +    AVFrame picture;
>>>>
>>>>> +    int width;
>>>>> +    int height;
>>>>
>>>
>>> Thanks. Will remove those and change the code accordingly.
>>>
>>>> redundant with AVCodecContext.width/...
>>>>
>>>> [...]
>>>>> +            if(avctx->pix_fmt == PIX_FMT_RGB48BE) {
>>>>> +                bytestream_put_be16(&dst, 
>>>>> MAKE10to16(RED10(rgbBuffer)));
>>>>> +                bytestream_put_be16(&dst,
>>>>> MAKE10to16(GREEN10(rgbBuffer)));
>>>>> +                bytestream_put_be16(&dst,
>>>>> MAKE10to16(BLUE10(rgbBuffer)));
>>>>> +            } else {
>>>>> +                bytestream_put_le16(&dst, 
>>>>> MAKE10to16(RED10(rgbBuffer)));
>>>>> +                bytestream_put_le16(&dst,
>>>>> MAKE10to16(GREEN10(rgbBuffer)));
>>>>> +                bytestream_put_le16(&dst,
>>>>> MAKE10to16(BLUE10(rgbBuffer)));
>>>>
>>>> this contains at least 6 unneeded shifts
>>>>
>>> Like this instead ?
>>>
>>> *dst++ = MAKE10to16(RED10(rgbBuffer));
>>> *dst++ = MAKE10to16(GREEN10(rgbBuffer));
>>> *dst++ = MAKE10to16(BLUE10(rgbBuffer));
>>
>> That is a good change as well
>>
>>
>>>
>>> or do you mean combining the MAKE10to16 with RED10? Personally I think 
>>> that
>>> would make the code less readable.
>>
>> well you have to remove the unneeded operations, how you do that is your
>> problem, droping all these macros is the cleanest way to write this IMHO
>> but its up to you how you do it, it just must be optimal in terms of
>> speed
>>
>
> Here is the patch with the changes. I'm not good at working with 
> bitshifting so I don't know how I can combine the bit shifting and masking 
> in 1 go instead of 2.

heres an example:

RRRGGGBBB & 000111000 ->000GGG000
000GGG000 >> 2 -> 00000GGG0
000GGG000 >> 5 -> 00000000G
00000GGG0 + 00000000G -> 00000GGGG

does that help or should i fix the mask&shifts?

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

No snowflake in an avalanche ever feels responsible. -- Voltaire
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