4K audio capture issue
Posted: Tue Dec 14, 2021 9:22 amHello,
TL;DR: My code only captures 1second of correct audio, then I get NULL packets from the callback.
I am developing a software to automatically record 3 video sources (2 x 4K quality, 1 x HD quality), as well as their audio, using the DeckLink Quad HDMI Recorder. So far, I have been able to create a solution that works for recording video without too many problems by taking inspiration on the SDK samples (Frames are dropped here and there, but this is also the case using BlackMagic's MediaExpress recording software. It is not that much of an issue for my project so I can just ignore this.).
Now the real issue is with the audio. Apparently, MediaExpress succeeds at recording the audio correctly. But not me, I am getting about 1 second of correct packets each containing 800 audio frames , but then after that first second, the IDeckLinkAudioInputPacket coming by the VideoInputFrameArrived callback is always NULL except once... about every second (only one audio packet per second).
The same happens when recording only one HDMI source instead of 3.
I just have the impression that there is a difference between HD and 4K formats, where HD allows a correct audio capture for 2 to 3 seconds from the start, whereas 4K only allows for less than a second of audio packets before the perturbation.
Do you please have an idea of what could cause such an issue ?
Thank you.
TL;DR: My code only captures 1second of correct audio, then I get NULL packets from the callback.
I am developing a software to automatically record 3 video sources (2 x 4K quality, 1 x HD quality), as well as their audio, using the DeckLink Quad HDMI Recorder. So far, I have been able to create a solution that works for recording video without too many problems by taking inspiration on the SDK samples (Frames are dropped here and there, but this is also the case using BlackMagic's MediaExpress recording software. It is not that much of an issue for my project so I can just ignore this.).
Now the real issue is with the audio. Apparently, MediaExpress succeeds at recording the audio correctly. But not me, I am getting about 1 second of correct packets each containing 800 audio frames , but then after that first second, the IDeckLinkAudioInputPacket coming by the VideoInputFrameArrived callback is always NULL except once... about every second (only one audio packet per second).
The same happens when recording only one HDMI source instead of 3.
I just have the impression that there is a difference between HD and 4K formats, where HD allows a correct audio capture for 2 to 3 seconds from the start, whereas 4K only allows for less than a second of audio packets before the perturbation.
Do you please have an idea of what could cause such an issue ?
Thank you.