Hi there, I need to hook into libmpeg2 so that I may do some processing on mpeg2 bitstream level. I have a working algorithm developed with the reference decoder (mssg's mpeg2v12.zip), but I would like to try on libmpeg2 because of its very fast decoding speed.
To decode the same mpeg2 video file, I have tried the reference decoder and libmpeg2's mpegdec. I found that both decoders have produced nonidentical frames (a few pixels at various position gets different values). Furthermore, by checking the IDCT process, I found that, for Intra block, DC value in DCT coefficient matrix, the reference decoder (getpic.c) is using signed 11 bits [-1024, +1024] but libmpeg2 (slice.c) is using unsigned 15 bits [0, 32768]. I thought this could be one of the reasons why the decoded frames are nonidentical. Why libmpeg2 needs to use a larger bit size ? Is there any way to configure libmpeg2 to use signed 11 bits for Intra block DC value, so that its behavior could become a bit closer to that of reference decoder? Thanks. Best Regards, pebble ------------------------------------------------------------------------------ BlackBerry® DevCon Americas, Oct. 18-20, San Francisco, CA The must-attend event for mobile developers. Connect with experts. Get tools for creating Super Apps. See the latest technologies. Sessions, hands-on labs, demos & much more. Register early & save! http://p.sf.net/sfu/rim-blackberry-1 _______________________________________________ Libmpeg2-devel mailing list Libmpeg2-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/libmpeg2-devel
