[FFmpeg-user] Decklink with ffmpeg audio desync

Dpto. Datos Television Costa Blanca datos at tvt-datos.es
Fri May 13 10:17:33 CEST 2016


El 12/05/2016 a las 21:19, Marton Balint escribió:
>> The actual command is:
>>
>> ./ffmpeg -re -f decklink -i "DeckLink SDI 4K at 2" -c:v mpeg2video -pix_fmt
>> yuv420p -aspect 16:9 -deinterlace -sc_threshold 1000000000 -b:v 3.5M
>> -minrate:v 3.5M -maxrate:v 3.5M -bufsize:v 2.4M -acodec mp2 -ac 2 -b:a
>> 128k-metadata service_name="TVT" -mpegts_service_id 123 -f mpegts
>> udp://224.0.0.247:5001?pkt_size=1316
>>
>> Just for info, the SDI input comes from a matrix that when switch betwen
>> sources have a little delay and ffmpeg return a NO INPUT SIGNAL DETECTED ->
>> INPUT SIGNAL DETECTED.
>>
>> Can the desync come from here?
> Yes, it is possible. Also I noticed you are using -re, there is no need
> for it, you cannot read from the device faster than realtime.
>
I've removed -re from the command, but if that doesnt help, how can I 
fix the desync? I have no way of "not having" the NO INPUT SIGNAL -> 
INPUT SIGNAL DETECTED problem.
Also, when the signal interrupts I see in the stream the colour bars. Do 
they come from ffmpeg or from the decklink card?

Regards.

-Daniel


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