FFMPEG DirectShow AJAX Audio capture

2
votes

I have an AJA board with an SDI input cable connected to it. The input signal has video and audio embeded.

The video is accesible through the "Vid" Pin and the audio is accesible through the "Aud 1-2" pin.

Well running DirectShow filter graphs:

OK graph 1

OK graph 2

"No Direct Show Audio Devices":

No Direct Show Audio Devices

I cannot get FFMPEG to correctly map the audio part.

This is what I tried without success to record the audio:

ffmpeg -y -rtbufsize 2048M -f dshow -i audio="AJA S-Capture KonaLHi- 0"  -acodec pcm_s24le -ar 48000 output.wav

ffmpeg -y -rtbufsize 2048M -f dshow -audio_pin_name "Aud 1-2" -i audio="AJA S-Capture KonaLHi- 0"  -acodec pcm_s24le -ar 48000 output.wav

this is the return error I get return error:

return error

The filter is NOT being used by any other software. I have no problems recording the video.

1
windowsaudioffmpegdirectshowcapture

1 Answers

1
votes

First graph is the special extension of the AJA Capture filter for Microsoft Expression encoder. This application (MEE) works only with separate video and audio Capture filters. Filter with connected audio pins is used only for transfer audio streams from filter with connected video pin (filter with connected video is master, filter with connected audio is slave). This is special mode of Capture filter, both filters are linked with hidden interface.

Second graph is the normal graph and filter should be used as shown on this picture.

About problems with ffmpeg - I studied ffmpeg code for DirectShow graph building. This code has many limitations. Please, check the Capture filter in GraphEdit (second graph). If filter works in GE, but doesn't work with ffmpeg, then ffmpeg has problems... I can't fix ffmpeg, I'm not a member of this group.

With best regards, DKN