Thanks Måns. The better result that I am seeking from libmpeg2 is better error detection and concealment.
I don't know if it is better in this way or not, but I have tweaked various CodecContext variables in libavcodec and I am still getting too many artifacts. Regarding non-compliant TS streams from LinuxDVB: I am currently using a DMX_SET_PES_FILTER with its pes_type member set to DMX_PES_OTHER. Since I a wanting video, perhaps I should change this to DMX_PES_VIDEO and perhaps I will get a standard TS/PES stream. Or maybe that's how DMX_SET_PES_FILTER works. All I know is that, after stripping-off the 4-byte TS header (and any adaption-field header, if present,) the remaining bytes are the raw compressed MPEG2 frames bytes. When I get a complete frame and decode/render it, I see the picture I expect. The libavcodec MPEG2 decoder is reporting normal sequences of I/P/B frames all along the way. Strange... Thanks for your insights. Bob Bob Ingraham <b...@brin.com> writes: > Hi All, > > I've written an app which uses the Linux DVB API to pull down an MPEG2-TS. > > Currently it: > > 1. Decodes the TS header > 2. Extracts the MPEG2 encoded frame > 3. Decompresses it with libavcodec (an ffmpeg library) > 4. Renders it with SDL > > But I wanted to try libmpeg2 to see if it's decoder will yield > better results than libavcodecs. Better in what way? > Questions: > > 1. Does libmpeg2 perform steps 1 through 3 above? No, it only does step 3. > 2. Can I just pass an compressed MPEG2 frame to libmpeg2 (without > any PS, TS or PES headers?) Yes, in fact you have to. > 3. Apparently, the Linux DVB API filter removes all PES headers and > hands me a TS stream with just the raw mpeg2 frames after the > TS/adaption field header. No, this is incorrect. > I don't think this is normal, because the MPEG2 spec says that mpeg2 > frames should be encapsulated within PES packets within the TS > frames. > > Does this seem odd that there are no PES header? Check again or change some setting. I know I have got proper TS streams from the Linux DVB interface. -- Måns Rullgård m...@mansr.com ------------------------------------------------------------------------------ Apps built with the Adobe(R) Flex(R) framework and Flex Builder(TM) are powering Web 2.0 with engaging, cross-platform capabilities. Quickly and easily build your RIAs with Flex Builder, the Eclipse(TM)based development software that enables intelligent coding and step-through debugging. Download the free 60 day trial. http://p.sf.net/sfu/www-adobe-com _______________________________________________ Libmpeg2-devel mailing list Libmpeg2-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/libmpeg2-devel
