[FFmpeg-devel] [PATCH 2/2] MxPEG decoder

[Michael Niedermayer]

On Wed, Nov 10, 2010 at 05:26:04PM +0300, Anatoly Nenashev wrote:
> On 09.11.2010 04:14, Michael Niedermayer wrote:
>> On Mon, Nov 08, 2010 at 05:27:18PM +0300, Anatoly Nenashev wrote:
>>    
>>> On 07.11.2010 16:28, Michael Niedermayer wrote:
>>>      
>>>> On Sat, Nov 06, 2010 at 05:10:41AM +0300, Anatoly Nenashev wrote:
>>>>     [...]
>>>>        
>>>>> +        /* search for start marker - 0xff */
>>>>> +        while (mxg->current_pos + FF_INPUT_BUFFER_PADDING_SIZE<   mxg->buffer_size) {
>>>>> +            uint32_t x;
>>>>> +            uint8_t *p = mxg->buffer + mxg->current_pos;
>>>>> +
>>>>> +            ret = get_partial_buffer(s->pb, p, 4);
>>>>>
>>>>>          
>>>> calling this every 4 bytes is slow
>>>>
>>>>
>>>>
>>>>        
>>> Replaced by 4-times get_byte calls.
>>>      
>> i suggest you look at START/STOP_TIMER
>> they are quite usefull to find out what is fast and what is slow
>>
>>    
> I've used it. 4-times get_byte() is slower than get_partial_buffer for 4  
> bytes. Now I've reimplemented this code to read 16 bytes at once. "16

try with 256 bytes

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

The worst form of inequality is to try to make unequal things equal.
-- Aristotle
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