Blackmagic Forum

Hi.
I have tried multiple capture with H.264 Pro Recorder.
I connected two H.264 Pro Recorder to one PC.
camera1 --- [HDMI] --- H.264 Pro Recorder --- [USB2.0] -+- PC
camera2 --- [HDMI] --- H.264 Pro Recorder --- [USB2.0] -+

I programmed capture application using Blackmagic DeckLink SDK 10.4.
The IBMDStreamingDeviceNotificationCallback::StreamingDeviceArrived() method called twice, and found two H.264 Pro Recorder device.
So, set BMDStreamingH264InputCallback callback to each device, and call IBMDStreamingDeviceInput::StartCapture() method.
My application seemed to have properly good working, but sometime NALpacket lost.

I have question, BMDStreamingAPI.dll support multiple capture?
I wont to capture camera1 and camera2 image at the same time.

I also tried this, but made the experience that it does not work to capture two streams in the same process. Having two processes capturing one stream each works.

Bump for this - has anyone managed to get simultaneous streams from 2 h.264 pro recorders in 1 process? Is it theoretically possible?

For reliability you would be much better off running 2 instances of an app so that if one crashed it didn't impact the other channel. I have run 2 copies of MXPTiny concurrently without any problem (H.264 ProRecorder and TVS as input sources) on a PC with 2 different USB 3 hubs.

Cool, I'm going to go that route. thanks Ian.
For the benefit of anyone else that comes across this thread:

When trying to record from 2 blackmagics with 1 process, I would intermittently get strange error messages and behavior:
- "invalid sync byte" messages, and data no longer coming through
- divide by zero exceptions when calling IBMDStreamingH264NALPacket::GetDisplayTime in IBMDStreamingH264InputCallback::H264NALPacketArrived

I suspect the SDK wasn't designed with this is mind.

Running 2 instances of my software and controlling a different device with each, I'm not able to reproduce any of those problems.