[Live-devel] JPEGVideoRTPSink and Restart markers

[Francisco Feijoo]

Thanks for the quick response Ross,

> 
> Note that the existing "JPEGVideoRTPSink" code already does this. You should not have to reinvent the wheel here.

I think I should explained this better. I don't know how to obtain the qFactor from one MJPEG image so I'm copying all the values from the original image to the new header. And then  TestJPEGVideoSource::qFactor() returns 255. Maybe this part is wrong and I need to calculate the Q, but how? is there an example of this somewhere?.

> 
> The JPEG transmitting code ("JPEGVideoSource" and "JPEGVideoRTPSink") currently don't support "Restart Marker Headers" (see RFC 2435, section 3.1.7).  You will need to update the (definition and implementation) of these two classes to support them.

Ok, I have been thinking on other possibility. Do you know if is possible to decode de MJPEG image to get a simpler version and remove the restart marker headers?

-- 
Francisco Feijoo
Software Engineer
J2K Video Limited
W: www.j2kvideo.com

El 27/10/2010, a las 02:39, Ross Finlayson escribió:

>> I'm trying to create a rtsp server to stream MJPEG images.
> 
> Ugh.  JPEG is a *terrible* codec for video streaming.
> 
> 
>> I have implemented a new TestJPEGFileServerMediaSubsession that creates a TestJPEGVideoRTPSink.
>> 
>> In TestJPEGVideoRTPSink::doSpecialFrameHandling I'm adding the quantization tables of the image into the header using setSpecialHeaderBytes
> 
> Note that the existing "JPEGVideoRTPSink" code already does this. You should not have to reinvent the wheel here.
> 
> 
>> This is working fine using some JPEG images, but fails with others.
>> 
>> I'm testing one image that has the marker 0xFF, 0xDD ( Define Restart Interval) and I think I have to do something else seeing this comment in the code
>> 
>> // Note: We assume that there are no 'restart markers'
>> 
>> So, what should I do with images containing restart markers and macroblocks?
> 
> The JPEG transmitting code ("JPEGVideoSource" and "JPEGVideoRTPSink") currently don't support "Restart Marker Headers" (see RFC 2435, section 3.1.7).  You will need to update the (definition and implementation) of these two classes to support them.
> -- 
> 
> Ross Finlayson
> Live Networks, Inc.
> http://www.live555.com/
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