From: Jan U. <esp...@ce...> - 2007-06-02 18:40:36
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Avidemux exported sequence, non-jerking video: Frames sequnce I(06) B(08) B(08) P(06) B(08) B(08) P(06) B(08) B(07) P(06) B(08) B(07) I(06) I frame i every 12 frame, so GOP = 12 ? B frames present, interesting. Image size 720x 576 Frame Rate 25.000 fps # of frames 332 frames Codec 4CC MPEG Video duration 00:00:13.280 Aspect Ratio Pal 4:3 (16:15) Extra properties: Packed Bitstream No Quartel Pixel No GMC No Audio: Codec AC3 Channels STEREO Bitrate 32000 Bps / 256 kbps Frequency 48000 Hz Audio duration 00:00:13.472 VBR No Kdenlive rendered, jerking video, the same clip: I(31) P(18) P(12) P(08) P(06) P(06) P(06) P(06) P(06) P(06) P(04) P(04) P(06) P(06) P(06) I (06) I frame i every 15 frame, so GOP = 15 (as was set in render profile) There are no B frames at all! Image size 720x 576 Frame Rate 25.000 fps # of frames 320 frames (12 frames missing, interesting!) Codec 4CC MPEG Video duration 00:00:12.800 Aspect Ratio Pal 4:3 (16:15) Extra properties: Packed Bitstream No Quartel Pixel No GMC No Audio: Codec AC3 (MP2 also tested) Channels STEREO Bitrate 56000 Bps / 448 kbps (128, 192, 256 kbps also tested) Frequency 48000 Hz Audio duration 00:00:12.768 VBR No forum.doom9.org: GOP's: I, P, and B frames explained... http://forum.doom9.org/archive/index.php/t-19436.html This information is interesting: I noticed some confusion about B frames, so I thought I would write down a quick explaination of an MPEG "GOP", or, "Group Of Pictures", as explained to me by a professor ... Oh, BTW, in MPEG2 at least, a GOP order is always IPBBPBBPBBIPBBPBB etc etc. (pending on your GOP size), but it is always 1 I, 1 P, and 2 B's, then you can stack more groups of "PBB"'s in that one GOP if needed (usually up to 15 total frames. ... This information indicates that Avidemux processed clip (cut and copy operation from original stream) is very close to this IBBPBBPBBPBBI.. order. And this works! Contrary, Kdenlive exported video is IPPPPPPPPIPPPP.. only stuff. No B frames at all. May this be related? Is this MTL or Kdenlive specific? What avlib parameters I can use to achive desired IBP frames combination? Any possible link? Thanks for any help Jan |