[FFmpeg-user] ffmpeg audio distortion using blackmagic

Flumotion Support support at flumotion.com
Mon Jul 23 12:51:08 EEST 2018

Hello everybody

If I understood you correctly to avoid corruption, I need to add the option
-async 1 -vsync 1 in my ffmpeg pipeline is this correct?, now i will make
some test with ffmepg 4 and the new driver included on version 10.11.1
Thanks for your help
Best regards

On Sun, Jul 22, 2018 at 9:10 PM, Marton Balint <cus at passwd.hu> wrote:

> On Wed, 18 Jul 2018, Flumotion Support wrote:
> Hello everybody
>> I have problems capturing a sdi flow with ffmpeg, I'm using a blackmagic
>> mini recorder pro, after a while of working the capture the audio is
>> distorted and the only way to fix it is to restart ffmpeg.
>> this is my pipeline
>> /usr/local/bin/ffmpeg -re -loglevel 48 -format_code pal -f decklink -i
>> DeckLink Mini Recorder -audio_input embedded -video_input sdi -vcodec
>> libx264 -crf 22 -preset:v veryfast -b:v 900k -pix_fmt yuv420p -acodec
>> libfdk_aac -ab 64k -ar 48000 -ac 2 -s 640x360 -f flv rtmp://
>> myserver.com:1935/test/live
>> I add an audio capture that is distorted from the second 10.
>> I will grow any help you can offer me.
>> Thanks in advance
>> King regards
>>>> croppedvideo.mp4
>> <https://drive.google.com/a/flumotion.com/file/d/1R_pjUps2xk
>> LYepeTxLIWKxqSy_qCnTF0/view?usp=drive_web>
> The audio gets corrupted during the DVE effect. Maybe there is something
> in the SDI signal that the decklink card does not like. (I had similar
> audio corruption when the PAL signal was mixed by an NTSC signal by mistake
> for a few seconds) Try using a frame sync. You can also try the HDMI
> capture by buying a SDI to HDMI converter. And you can also try the
> BlackMagic support of course, as this is almost surely a BlackMagic issue.
> Regards,
> Marton
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