H.264 glitchy video and some experience with the device so far

[Andrew Stone]

Guess I am going to have to phone tech support to get on this “beta list”. Really shouldn’t have to do this… simply post beta builds on the support website, in my view.

One thing that struck me as soon as I began using the Media Express app is fixed sizing of the UI into the compact or full screen size which actually into full screen as it goes “off screen” on 15″ laptops. The fixed sizing of the UI particularly the preview size destines the app to be a resource hog. It seems to me there is NO reason why the user shouldn’t have the ability to resize the preview. I understand the reasoning behind not being able to disable it as there is no proof positive indicator that things are recording as they should, however, if it is known the preview is sucking up CPU cycles and the app is far from optimized why aren’t you allowing the ability to get the preview down to a postage stamp size to free up the CPU for the actual encoding or decoding?

-Andrew

—
Steadicam & Camera Operator

[Richard Freemantle]

As the input preview seems to be a reasonably hot topic just thought I’d pitch some ideas.

Possible alternate preview modes:

1: Off = Dont decode the stream at all
2: Minimum = Just check stream integrity ie. gop/frame headers ok (pos unrequired)
2: Reduced = Only decode I-Frames in low priority background thread (allowing skipping frames if neccessary)
3: Full

The thinking being that if CPU use is an issue, a user could start at full (or reduced) preview mode & then drop to a lower level once they are sure everything is connected ok etc…

This would certainly make me a happier customer anyway!

[Eric Lanouette]

Andrew,

Decoding H.264 with GPU hardware acceleration off can require a lot of CPU if the file use some high profile options. H.264 Pro Recorder use high profile @ 4.0 level.

Scaling it down during playback won’t change anything to CPU use because it have to decode the whole full size picture then preform a scaling procedure. So even if you display it at the size of a stamp, it will use about the same ressources.

If you are on a Mac you can test it by recording a 1080 HD clip using the H.264 Pro Recorder then open it in the old QuickTime 7 as it didn’t use GPU hardware acceleration. Scale it down then check the CPU usage.

Eric

[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!!

[Jack Welten]

Hello Kristian,

In my opion, the main idea behind this device is to produce H.264-files with a low spec computer, the heavy encoding work should be done by H.264 Pro Recorder. I still think this is possible.

I see the H.264 Pro Recorder more like a VTR which uses a laptop as storage, so no need for a preview (ok would be nice). The stream should correctly be encoded by the firmware and is currently max 20 Mbit/s, so never a problem to store for any computer. The glitches are a firmware-problem (main problem), the heavy CPU-usage is an avoidable softwareproblem.

Again a small program with one start/stop button, one preferences button, a box for the directory/filename and a displayed timecounter (recordingcheck) would be enough,

with kind regards

Jack

[Johan Vermeire]

Same Here guys, a lot of troubles
Random glitches, loosing sync, audio sometimes not detected, when i got lucky after a few times of plugin & unplug i have 2channel audio.

Whitout TBC analoge video does not show up correct.

Media express always goes back to NTSC settings -> i always have the new project settings warning.
Media express also quit sommetimes.

Missing features in software.

More decent presets
Real Time cropping
Trim and split of large video files.

It seems like a rush rush product at the moment 🙁

[David Debono]

Hi Kristian Lam

Re: Glitchy capture issues

Note – I sent an inquiry on Aug 7th to BlackMagic Support requesting they send a link to download the new test build you referenced re Glitches in capture. I copied your response to this thread along my original posting but I have had no response from BM to date.

Can you please nudge this along with support as the h.264 Pro unit is not usable in its current form?

Thank you

David Debono

[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.

[David Debono]

Thanks Mark for the links!

I will give the new software at try.

David

[Eric Lanouette]

If someone have the URL for the mac version, please post them. I already try to change .zip by .dmg in the url but it doesn’t works.

Eric