Hi Ron That formula it's very useful! Thanks. I have a silly question (sorry for it). If I understand correctly 8000000 is the symbol rate and 12901961 is the TS rate? Correct?
The multiply by 2 is because Tx signal is QPSK? If that's so then it will be 1 for BPSK, 3 for 8PSK and so on.... Am I right? Thanks! Raydel El jue., 7 de feb. de 2019 7:26 PM, Ron Economos <[email protected]> escribió: > First, you have to match the TS rate to the symbol rate. The equation is: > > Symbol rate * 2 * 188/204 * code rate > > For the example flow graph: > > 8000000 * 2 * 188/204 * 7/8 = 12.901961 Mbps > > Second, you need to constrain the video bitrate to fit into the selected > TS bitrate. With ffmpeg, something like this: > > ffmpeg -i test.mp4 -c:v libx264 -b:v 10M -minrate 11M -maxrate 11M > -bufsize 8M -c:a copy -muxrate 12901961 test.ts > > For SD video, a smaller bufsize like 2M should be used. > > Ron > On 2/7/19 15:15, Alban Meffre wrote: > > Hi All > did some transmission test in DVB-S tonight > TX : ffmpeg + gnuradio + pluto SDR > RX : RTLSDR + sdrangel > it works but there are some gaps in the received signal because the TS > stream bitrate is slightly less to the maximum usable bitrate > > is it possible to add some bit stuffing at DVB-S modulator side to make to > output power constant ? > > Bob > > -- > Alban MEFFRE F4GSW > > > > _______________________________________________ > Discuss-gnuradio mailing > [email protected]https://lists.gnu.org/mailman/listinfo/discuss-gnuradio > > _______________________________________________ > Discuss-gnuradio mailing list > [email protected] > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio >
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