Em Wed, 22 Jul 2009 12:02:48 -0400 Devin Heitmueller <dheitmueller@xxxxxxxxxxxxxx> escreveu: > Hello Mauro, > > As far as I know, the em28xx has no capability to adjust the frame > rate. It will forward the frames at whatever rate the ITU656 stream > is delivered from the decoder. Ok. So, the fps changing will be limited to the decoder and/or sensor that supports it. > I also don't think the tvp5150 will > deliver frames at any rather other than the NTSC/PAL standard in > question (but I would have to double-check the tvp5150 datasheet to be > sure). On a very quick check on saa7114/saa7115 and tvp5150, I couldn't find any way do do spatial decimation to reduce fps. So, it seems that we'll have this feature only with webcams where such type of control is common. > I would like to spend some time looking closer at the formula used to > calculate the set_alternate() call. I just haven't had the time to > invest in such an investigation given all the other stuff I am working > on right now (in particular the three or four em28xx devices I am > adding support for, the xc4000 driver work, and hvr-950q analog > fixes). Maybe that magic calculus took from experimentation are due to vbi and/or audio streams. It would be nice to adjust it to be less conservative. > I didn't know about the 80% utilization cap for isoc, so thanks for > providing the reference to that previous thread, which has some pretty > interesting information. Anytime. Cheers, Mauro -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
