Renato, How would one go about rendering the stream for only the luminance plane? Do you mean going into my MF H.264 encoder? You must. Otherwise I don't know how to analyze the compressed output to omit the color. And for the MF H.264 encoder, I don't think there's any way to tell it to do only Y. Is this what you were suggesting? If so, then how would one get around the problem I just indicated? If not, what did you really mean.
On Fri, Jan 4, 2013 at 8:47 AM, Renato MAURO (Libero) <[email protected] > wrote: > NV12 is similar to I420 (or YUV420, if you prefer), so it is 12 bit per > pixel, 8 for luminance and 4 for CrCb (or U and V if you prefer). See > http://www.fourcc.org/yuv.php#NV12. > Obviously, "4 bits for CrCb" means that each byte is used for 4 pixels (a > 2x2 quad), and so NV12 is a planar only format. > > So: 640 x 480 x 1,5 = 450 kBi = 3.51 Mbi uncompressed => 3.51 Mbi / 160 > kbi = 22,5 times. > > I suggest to render the stream for the luminance plane only (like old TV > sets!!): if you get a good output, the problem is the way the renderer > works on the U and V plane. > > > Regards, > > Renato > > > Il 04/01/2013 13.49, [email protected] ha scritto: > > Thanks very much for your help, Ross. > > BACKGROUND: (CLARIFICATION ONLY) Indeed I only have one thread calling > doEventLoop(). That's all I meant by my penultimate background sentence. > The last background sentence points out a separate thread for MF, that's > independent of Live555, and is in fact the thread taking advantage of the > one exception within Live555: calling triggerEvent(). > > FOLLOWUP QUESTION: Having incorporated your question one answer, my > output is better and now only "very poor" rather than "horrible". My > uncompressed stream is 640 x 480 x 30fps. It passes through NV12 format, > which when considered as YUV I think has about 16 bits of info per pixel (8 > bits for Y, 8 bits for UV, like YUV422). So an uncompressed 640 x 480 > frame should have nearly 5Mbits of info. However, the compressed frames > I'm sending to Live555 are generally 160kbits each (after an initial > 384kbit frame). I realize you're not responsible for MF, but perhaps you > can give your opinion, please. This suggests to me that my MF H.264 encoder > is compressing roughly 5Mbits/160kbits = 31 times. Perhaps my remaining > "very poor" quality is because this is too much compression. I > reconfigured the encoder for 10 times the average bit rate, but this > typical 160kbits/frame output size didn't really change. DO YOU AGREE that > I ought to be able to increase encoder output quality by increasing average > bit rate, and that the 160kbits per compressed frame should rise toward > 5Mbits? > > Thanks again. > > > > > > _______________________________________________ > live-devel mailing > [email protected]http://lists.live555.com/mailman/listinfo/live-devel > > > > _______________________________________________ > live-devel mailing list > [email protected] > http://lists.live555.com/mailman/listinfo/live-devel > >
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