Re: [mpeg2-dev] libmpeg2 conformance test for main profile of mpeg2

[Peter Gubanov]

Yes, libmpeg2 passes conformance tests for MPEG-2 Main Profile and MPEG-2 4:2:2 Profile. MPEG-1 video is not a subset of MPEG-2 video, yet the algorithms are very similar, and most decoders combine MPEG-1 and MPEG-2 video decoder in one engine. Libmpeg2 is guaranted to decode MPEG-1 with constrained parameters, however, there are no limitations for MPEG-1 similar to levels and profiles of MPEG-2, and thus one can create MPEG-1 stream requiring very large VBV buffer, for instance, and this stream will not fit libmpeg2 internal buffers. However, there is no industry standard that allows MPEG-1 streams with parameters exceeded libmpeg2 limitations. Peter Jihee Kim wrote: Dear experts,   I read the following sentence at http://directory.fsf.org/libMPEG.html “Conformance - libmpeg2 can decode all mpeg streams that               conform to certain restrictions: "constrained parameters" for mpeg-1, and "main profile" for mpeg-2” About these words, I am wondering the following items. I. Please let me know the libmpeg2 decoder passed the conformance test (ISO/IEC 13818-4) for main profile of MPEG2. I got the result that the pixel values from libmpeg2 and w6737 (mpeg2 reference code) have than +-2 term. 2. I knew mpeg2 involved mpeg1 and I guessed if passed the conformance test for the main profile of MPEG2, then MPEG1 should pass the test.    According to above words, however, MPEG1 passed only for the bitstream with “constrained parameters”, is it right?    I would appreciate hearing from you in advance.   Thanks, Kim ------------------------------------------------------------------------- Using Tomcat but need to do more? Need to support web services, security? Get stuff done quickly with pre-integrated technology to make your job easier Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronimo http://sel.as-us.falkag.net/sel?cmd=lnk&kid=120709&bid=263057&dat=121642 _______________________________________________ Libmpeg2-devel mailing list Libmpeg2-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/libmpeg2-devel

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