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F5OEO / rpidatv

Digital Television Transmitter on Raspberry Pi
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Piping avc2ts output to rpidatv input #44

Closed csarmo closed 7 years ago

csarmo commented 7 years ago

I don't know if you already have done this, since i haven't seen the command in the code. Is it possible to direct piping the acv2ts output to the rpidatv using the | for redirection ? What could be a example of the command if the answer is yes.

F5OEO commented 7 years ago

rpidatv don't get input from stdin. So passing avc2ts -> rpidatv is done through a pipe. See a.sh script to see example : 

sudo $PATHRPI"/rpidatv" -i videots -s $SYMBOLRATE_K -c $FECNUM"/"$FECDEN -f $FREQUENCY_OUT -p $GAIN -m $MODE -x $PIN_I -y $PIN_Q &
$PATHRPI"/avc2ts" -b $BITRATE_VIDEO -m $BITRATE_TS -x $VIDEO_WIDTH -y $VIDEO_HEIGHT -f $VIDEO_FPS -i 100 -o videots -t 3 -p $PIDPMT -s $CHANNEL $OUTPUT_IP   &
csarmo commented 7 years ago

I know both programs and the parameters that need to be setup in both, but what i don't know is what type of pipe use in order to immediate transmit live video from the avc2ts to the rpidatv without storing the .ts file somewhere.

F5OEO commented 7 years ago

just make a fifo : mkfifo video.ts and refere to it on both softwares.. that's it

csarmo commented 7 years ago

I was testing avc2ts with rpidatv with my raspberry Pi Zero. I was using the next commands:

##################### PLACING INTO THE BIN FOLDER ########## cd /home/pi/rpidatv/bin

##################### SURE TO KILL ALL PROCESS ######################

sudo killall avc2ts >/dev/null 2>/dev/null sudo killall rpidatv >/dev/null 2>/dev/null

#################### CREATE THE FIFO PIPE ###################

sudo rm videots mkfifo videots

################## RUNNING THE COMMANDS ################

sudo ./avc2ts -b 330000 -m 462000 -x 416 -y 234 -f 40 -i 100 -o videots -t 0 & sudo ./rpidatv -i videots -s 500 -c 1/2 -f 437.5 -p 3 -m RF &

At the beggining the program just run awesome, but after some minutes the leandvb start showing lots of errors, some of those are: PCR call too late, TS discontinuity, more than 5 seconds late, and more. Looks like the Raspberry Zero is too slow when both programs are running. The video (i use a raspicam of 5 MP) looks good just before the errors. In some tests i could watch the QPSK Symbol clouds, the percentage increasing and then decreasing to zero, and keep doing this; maybe this is related with the ts dicontinuity error.

If you need some image of this errors, ask me. Let me tell you that those are greats programs.

F5OEO commented 7 years ago

Seems that your bitrate calculation is not good for the mux bitrate : Bitrate = 2_SR_188/204 So for SR 500 FEC 1/2 : 2 * 500 * 1/2 * 188/204 = 460784 bit/s (instead of 462000). It means that avc2ts overflow the mux which could block the process after some time. Carefull also that even we set a target bitrate for video (-b330000) , there could be some peaks in bitrate. Suggest to decrease the video bitrate. Is there any reason why you have a framerate of 40 fps instead of standard 25 fps ?