[Live-devel] RFC 2435 compliance

[Alexandr Němec]

Dear Ross,
 
we came across an interesting issue with JPEG video (transmitted via RTP) not being decoded correctly. We tracked down this issue to the fact, that live555 seems to use different default JPEG quantizer tables (luma and chroma - see JPEGVideoRTPSource.cpp line 271, latest source code) than defined in RFC 2435 Appendix A. The algorithm of generating the resulting quantizer tables is, however, the same. So for RTP JPEG implementations using Q values <= 127, the resulting JPEG frames are distorted.
 
Could you please explain the difference here? We use live555 (the openRTSP application) as a reference for proving RTSP/RTP standard compliance, but I have never noticed this difference before.
 
Thank you very much.
 
Alex