- Posts: 1
- Joined: Tue Jan 03, 2017 9:12 am
Wed Jan 04, 2017 4:23 pm
Hi
We developped a Decklink directshow based video player. It uses Decklink Video renderer and Decklink audio Renderer directshow filters.
We need to play audio that is 20-bit 48K PCM, and output it embedded in the HD-SDI output. The audio samples in the output must be also 20 bit. This is because the audio is Dolby-E encoded. If audio samples are converted to 16 bit then cannot be decoded.
Testing it in GraphEdit we see that Decklink Audio renderer filter input pin accepts 16 and 24 bit PCM audio, but the SDI output seems to be always converted to 16-bit. Connecting an external Dolby-E decoder at the output fails to decode the embedded audio.
We tested it using the BlackMagic WDM renderer filter. We saw that it works. The filter accepts 32 bit PCM on its audio input pin and SDI audio can be decoded with the external DolbyE decoder. But using it instead of Decklink video/audio renderers has other problems: Poor seeking / scrubbing support, need to convert video color space and audio sample depth, and also we experimented hangs while graph pausing/start/stop/seeking.
Is this a bug? It appears to be a Decklink Audio Renderer bug. It is not a hardware issue, as the WDM renderer works.
Please can you add support for 20-bit audio playback with the Decklink Audio rendeder filter?
Regards
We developped a Decklink directshow based video player. It uses Decklink Video renderer and Decklink audio Renderer directshow filters.
We need to play audio that is 20-bit 48K PCM, and output it embedded in the HD-SDI output. The audio samples in the output must be also 20 bit. This is because the audio is Dolby-E encoded. If audio samples are converted to 16 bit then cannot be decoded.
Testing it in GraphEdit we see that Decklink Audio renderer filter input pin accepts 16 and 24 bit PCM audio, but the SDI output seems to be always converted to 16-bit. Connecting an external Dolby-E decoder at the output fails to decode the embedded audio.
We tested it using the BlackMagic WDM renderer filter. We saw that it works. The filter accepts 32 bit PCM on its audio input pin and SDI audio can be decoded with the external DolbyE decoder. But using it instead of Decklink video/audio renderers has other problems: Poor seeking / scrubbing support, need to convert video color space and audio sample depth, and also we experimented hangs while graph pausing/start/stop/seeking.
Is this a bug? It appears to be a Decklink Audio Renderer bug. It is not a hardware issue, as the WDM renderer works.
Please can you add support for 20-bit audio playback with the Decklink Audio rendeder filter?
Regards