On Wednesday 12 May 2004 09:07, you wrote: > Hi all, > > after some explanation from Gerd Knorr, and after reading the driver's > code, I understood the buffering problem that I was having, and I am > doing some experiments for tuning the TS_NR_PACKETS value (hey, with > TS_NR_PACKETS = 1 I get no jitter on the PCR!!! But the stream is > corrupted...)
argh. > In the meanwhile, I have some other questions about the MPEX board, and > the driver: > 1) I see that the generated TS has video PID = 256, audio PID = 259, and > PCR PID = 260. Is it possible to change such values? Looking at the > driver, they seem to be hardcoded in it, but I hope that the hardware > permit to configure the PIDs... How difficult would it be to fix the > driver? yeah, its possible - you'd have to write the values you want to the TS PID registers, and recalculate the (currently hardcoded) PAT/PMT tables. The driver doesn't do this right now. BTW: I think the driver would have to stop+start the encoding process to change the PIDs - I doubt its doable on the fly. > 2) Would it be possible to generate a TS with PCR PID = video PID? I think so - you can specify which PID should contain the PCR independently of specifying the video/audio PIDs... but again the driver doesn't yet expose this interface to userspace. > 3) How can I set the stream parameters (bit rate, CBR vs VBR, ...)? I > think I must use some ioctl() on /dev/video0... Where is is documented? There aren't any standard APIs for setting that sort of thing in linux, so I had to make it up myself. Have a look at MPEG_SETPARAMS in saa6752hs.h though. I tried to expose as many of the bitrate parameters as I could. > 4) It seems that the audio volume is a bit low (I have an MPEX board > without tuner, BTW). I already tried things like "v4lctl volume 100", or > similar, but it is still low... Is anyone seeing similar problems? Any > suggestion? I always just adjusted the analogue input volume - not sure if its configurable in the hardware (and it won't be in the saa6752hs bit if it is).