[FFmpeg-devel] h263 - svq3 optimizations

[Benjamin Larsson]

Yohann Martineau wrote:
> On 3/17/09, Panagiotis Issaris <takis.issaris at uhasselt.be> wrote:
>   
>> Hi,
>>
>> On Tuesday 17 March 2009 13:38:02 Jason Garrett-Glaser wrote:
>>     
>>> On Tue, Mar 17, 2009 at 4:16 AM, Yohann Martineau
>>>
>>> <yohann.martineau at gmail.com> wrote:
>>>       
>>>> hello,
>>>>
>>>> h263 and sorenson spark have some common elements. Both have picture,
>>>> MB and block layers. And it seems that block layer is also very
>>>> similar between those two codecs.
>>>>
>>>> Do you think it would make sense to work on transcoding optimizations
>>>> between those two codecs?
>>>>         
>>> Perhaps you meant H.264?  SVQ3 is quite similar to H.264, not H.263.
>>>       
>> No, he's right, Sorenson _Spark_ and H.263 are actually very similar. They
>> differ mostly in header structure and ranges of the coefficients.
>>
>>     
>
>
> Actually, I meant sorenson spark, which is used for adobe flash player
> (9+) webcam video streaming. I thought it was SVQ3, is it SVQ1?
> There's a page on the wiki about sorenson spark, but it does not say
> if it's svq1 or svq3 (or something else?):
>
>   http://wiki.multimedia.cx/index.php?title=Sorenson_Spark
>
> I've read swf 10 format specification on adobe site and it seems that
> svq3.c matches the video chapter, but I may be wrong.
>   

Sorenson Spark is almost h.263. A bitstream filter might be able to covert directly to h.263/mpeg-4. SVQ3 is almost h.264, SVQ1 is a custom beast.

MvH
Benjamin Larsson