[FFmpeg-user] Decklink with ffmpeg audio desync

Marton Balint cus at passwd.hu
Wed May 11 23:42:07 CEST 2016

On Tue, 10 May 2016, Dpto. Datos Television Costa Blanca wrote:

> Hi Marton,
> Thanks for replying. And without resampling you mean? Sorry, Im far away 
> of having video skills.

Do not top post. Try to figure out based on the ffmpeg command line manual 
what your command actually does.

> ./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 -ar 44100 -af aresample=async=1:min_hard_comp=0.100:first_pts=0
> -metadata service_name="TVT" -mpegts_service_id 123 -f mpegts
> udp://

With -ar 44100 you are resampling the initial sample rate of the captured 
source (48000) to 44100. You are also manually specifying a resample 
filter with -af resample. Try your encoding without these options.


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