[Mark Brunkhart]

A little more testing done, and it appears the newest firmware solves the glitches at 720p. (Thanks BlackMagic!)

Some additional information on the excessive CPU usage. On an Intel Core 2 Duo 2.93GHz with a NVIDIA GeForce 310:

Capturing or previewing 5Mb/sec off the ProRecorder:
70-80% CPU usage
Capturing or previewing 20Mb/sec off the ProRecorder:
95-100% CPU usage

Playback of 5Mb/sec captured from the ProRecorder using ffdshow:
5-10% CPU usage

So playback/preview of the H.264 being generated can be done very efficiently.

Finally, is there any developer information available on the DirectShow filters being used? Can they be used outside of BlackMagic apps? We might just be able to modify our own capture app to use the BlackMagic hardware if it’s possible to use the filters ourselves.
From some of the filters BlackMagic installs on the machine (including a BlackMagic decoder that I suspect is the source of the slowness), it looks like this may be just a straightforward DirectShow app.

Would it be possible for BlackMagic to just provide an option where the user could use a different decoder (perhaps provide its GUID or provide defaults for common ones) or just render out from the pin using whatever DirectShow filters are present?

One more feature request (in addition to AVI output, I-frame spacing configurability, better CPU usage, compact GUI, and better support for multiple devices ;-): a capture limit…file size and time limits that can be set in preferences to stop capture after a set period.

If you’re recording longer videos, this is a must to avoid having to monitor the capture just to press the stop button when it’s done.

[Mark Brunkhart]

David,

I spoke to support last week, and they apologized for being very far behind on the e-mails. (I think one of mine hadn’t been answered for 3 weeks.) I got the sense that they’d given up on trying to respond. If you want a response, I think you need to call.

But, to save you the call, we did get the following links out of them yesterday:
https://seeds.blackmagic-design.com/H264ProRecorder/DesktopVideo_8.2.1rc3.zip
https://seeds.blackmagic-design.com/H264ProRecorder/MediaExpress_2.4rc45.zip

Initial testing suggests the glitches are gone, but high CPU usage and the other issues discussed in this thread remain.

[Mark Brunkhart]

Kristian,

Thanks for the response. Glad to hear that there’s a build out there that will solve the glitches. Look forward to trying it.

Echoing some other comments on the board plus a few other features we’d like to see:

– Lower CPU preview decoding AND an option to turn it to I-frame only decoding. If you decode the exact same ProRecorder-created video with freely available ffdshow, the CPU usage is MUCH lower than when decoded in your software. It seems the decoding library being used for the preview is a resource hog.

– Smaller interface. The “compact” interface is huge. I support the suggestion for a minimal, resizable GUI with ‘start/stop recording’, preview, time captured so far, filename, a frame drop count and nothing else. Capture is one of those things that you start and then wait a couple hours for. During those couple hours, you’d like to move it to a corner of the screen and mostly ignore it.

– Software isn’t set to be ‘single instance’ so you can buy multiple devices and use them on the same machine (without the hack of making a copy of the .exe)

– AVI output files are a must for anyone on a PC. (We also have the rather unique need to allow these AVI files to be read while they are being written…just a flag to turn off the read-locking on the file when it’s created…maybe a registry parameter or something we could toggle since I imagine there aren’t many out there who need this feature.)

– Support for Windows XP and Windows 7 32-bit would be nice.

– Better ability to set detailed encoding parameters. We need to be able to set I-frame spacing. Recording profiles are nice, but for a professional level device, the more variables we can set related to the codec, the better.

Thanks for being on the forums and being responsive to the feedback here!!

[Mark Brunkhart]

Eric,

Thanks for the response. You just saved me from testing an SSD drive which was on my list. With both of our experience combined, I’m more convinced than ever that the problem is inside the ProRecorder box.

Overall, I agree with your assessment that people considering buying the device should wait until/if the box works. With the glitches and the massive CPU usage just for preview, I agree that it is useless in its current state.

Mark

[Mark Brunkhart]

We experienced the same 100% CPU issue using fairly modern Core 2 Duo’s with video preview. This led to very glitchy results when the CPU attempted to do even minor tasks. Typical H.264 decoding using ffdshow on the same machine also exhibited much lower CPU usage similar to your description, so it seems the software decoding being done in Media Express is somewhat inefficient.

Also, very important…you get much better performance with an NVIDIA card where much of the decoding can be done on the card. We swapped in a GeForce 310, and dropped CPU usage dramatically (although still surprisingly high for just streaming data from the device to the disk). This might be a solution for you rather than upgrading the machine.

I am in agreement that some type of ‘no preview’ or ‘low quality preview’ would help particularly during capture, or better yet, a more efficient H.264 decoder would help a lot.

[Mark Brunkhart]

I was on the phone with tech support this morning and asked the same question. The answer is ‘yes’, but you have to make a copy of the executable and run it as a separate program.

The problem is that Media Express only allows one instance of the software (this would be nice for BlackMagic to change), so you have to trick it into starting two instances by having two completely separate executables.

At that point, you should be able to open the two copies separately, select the different devices, and do two captures.

I haven’t tried this yet as we’re still testing our first H.264 ProRecorder. If you have the chance to try it, I would love to hear how it goes before we invest in a second one.