Blackmagic 8-bit MJPEG vs CineForm HD

[Richard Leadbetter]

Hi there,

Much has been made of the free Blackmagic MJPEG codec bundled with the Intensity, so I thought I would give it a go.

I linked up our somewhat specialised video games HD capture hardware with the Blackmagic 8-bit MJPEG VFW codec today in order to compare it against CineForm. It may be an unfair test as our capture software can address the CineForm DirectShow encoder directly and I am unsure whether the BMD codec has a DirectShow version of its encoder, and if it does, how much of an improvement it is. Notes though:

1. The VFW codec wouldn't accept a YUV 4:2:2 input, I had to feed it 24-bit RGB (CineForm will accept both but flies with YUV 4:2:2)
2. A Pentium 4 3.0GHz CPU with HT really struggled to achieve 30fps capture at 720p without dropping frames. Fed YUV 4:2:2, CineForm has no problems on this CPU
3. The codec does appear to be multi-threaded so should do much much better on a strong Core 2 platform

Picture quality then: well, putting uncompressed YUV 4:2:2 next to CineForm, I have to use zoom in Photoshop on a specific still to spot any differences. And even then half the time I'm not sure if I am actually seeing any difference! In motion it definitely lives up to its 'visually perfect' billing.

Blackmagic MJPEG has typical JPEG artefacting, especially around lettering (the usual pixel fuzziness around lettering, for example). On fine detail it's really not that good either while CineForm is practically flawless.

Filesizes then, and here's a real surprise.

One minute of 'not that challenging' video games 720p/30 footage, captured at 24-bit RGB and compressed on the fly with the mathematically lossless Huffyuv codec was dubbed into various codecs by VirtualDub. Results are:

Huffyuv: 2.23GB (double that for completely uncompressed)
CineForm HD (Low Quality Setting/Progressive): 462MB
CineForm HD (Medium Quality Setting/Progressive): 590MB
CineForm HD (High Quality Setting/Progressive): 757MB
Blackmagic MJPEG (there are no quality settings): 513MB

I was under the impression that the bandwidth used by the MJPEG compressor was lower than CineForm, and it is on all but the lowest quality setting - but not by an appreciably useful margin. Certainly not considering the gulf in quality. I think this is a fair like-for-like test too as (and I might be wrong) the CFHD VFW codec as used by VirtualDub only operates in the 8-bit domain, just like the MJPEG one.

I should also point out that the 462MB 'low' quality CineForm HD file still looked considerably better than the MJPEG in lack of artifacting, retention of key detail etc. It's also worth mentioning that video games capture is characterised by an infinite depth of field, sharper edges - all the stuff that makes compression difficult and artifacting easier to spot.

So in every appreciable way (aside from cost), CineForm HD significantly (if not massively) out-performs the MJPEG codec based on my experience.

[Richard Leadbetter]

Thanks to some input from David Newman, I know why the Blackmagic codec doesn't support YUY2 - it pumps out its 8-bit 4:2:2 output in the UYVY pixel format instead. Performance of the MJPEG codec is a lot faster then fed this directly. However, quality is stil pretty rough up against CineForm.

Another thing I have observed seems to be a total lack of keyframes in the AVI files. You can't scan through them as you would a CineForm or uncompressed AVI - if I skip ahead through the AVI to the end, I have to wait a long, long time for it to process all of the frames and then finally show the one I want!

It makes it pretty much unusable in my opinion. I'll try some Premiere capture next and see what's what, but I'm standing with my original findings vs CineForm. Interesting as a freebie, but I've been working with HDMI and DVI capture for quite some time on my video games projects and when you're dealing with that level of clarity, you've essentially got a choice between a mathematically lossless codec like Huffyuv, or a hard disk mangling uncompressed capture (best have four drives in RAID-0 for that). Neither is a workable solution.

For me only CineForm works if you want to maximise your return from the lossless input, while still having a well-compressed file.

[Daymon Hoffman]

Richard,

Thank greatly for your post.

I'm keen to have a set-up myself that will be capable of capturing gaming style things in HD (think Gran Tourismo HD or GT5). Hope its ok i'd love to pick your brain about this stuff? :)

Is it possible to capture using the Intensity card, from the HDMI output of a PS3?

Considering i've got a Dell 2405 24" LCD that is not capable of HDCP i can't use the HDMI output. I've heard the Intensity card conforms to HDCP connect and thus wont capture from such sources. Is this the case here... am i completely out of luck from digitizing replays and gaming footage via this method from the PS3?

Also, you mention HuffYUV. I used to use that codec in my analog capping days. Does it handle HD resolutions ok? I may use it as spending big on Connect (or which ever one i'll need) won't be something i'm willing to do just for a hobby atm.

How do you go about such a thing? What consoles do you capture from? Hope you don't mind me posting these queries here.


Regards,
Daymon

[Richard Leadbetter]

A retail PlayStation3 is out of the question for HDMI capture, unfortunately due to HDCP issues. Xena HLe or Decklink HD would work for analogue component up to 1080i. Both are good value (HLe especially in the Prospect combo offer CineForm has). Obviously quality won't be as good as HDMI, but I should point out that Xena HLe has been approved by Microsoft for component capture for video projects aimed at Xbox Live and for event usage (E3) and their standards are very, very high.

For the purposes of this test, I captured at 24-bit RGB in the mathematically lossless Huffyuv codec using our own hardware configuration (not Intensity which only gives you YPrPb 4:2:2 no matter what input you feed it) then 'dubbed' into the CineForm and Blackmagic codecs. PS3 development hardware has no Blu-ray playback, so Sony is able to supply an HDCP free option.

With regards Huffyuv, this was the codec I was using before I 'discovered' CineForm, and before we integrated CineForm with our own hardware solution. It can handle 720p/60 capture from YPrPb 4:2:2 (YUY2) sources on any 3.0GHz+ Pentium 4 though it struggles badly with 24-bit RGB. File sizes are colossal though, requiring RAID-0. We gained some efficiency by adjusting the way it compresses progressive content and also put some threading into it, but until we start to capture 1080p/60 we have no idea how successful that is because it's already so damn fast. By that point we would hope to be using the CineForm 4:4:4 codec any way, just as the current CineForm codec has effectively wiped out the need for Huffyuv when capturing YUY2.

The discussion is kind of moot in that out of the box, you can't capture into Huffyuv with Intensity, even if you could capture PS3 in the first place. As I said in my last post, Intensity outputs its 8-bit 4:2:2 output in the UYVY pixel format instead of YUY2, so only Blackmagic's own codecs work with it. That being the case, CineForm's HDLink tool becomes the best option.

By the way, the development PS3 sans HDCP looks beautiful on the 2405FPW, I have one myself. Maybe you could sell off your 2405FPW and get an HDCP-compatible 2407WFP. I understand that A04 revision onwards of this panel is excellent.

[Daymon Hoffman]

Richard,

Thanks for your response. Hmm well that makes my decision difficult. Was really hoping to be able to capture PS3 output via HDMI. I may update my 2405 to a 2707 or the Samsung 27" when its out. That will solve one problem of HDCP from PS3 (and any other device i get should i want to hook it up to that monitor). I heard some talk about a component > HDMI adaptor. This *might* do me for capturing from the PS3. But i'll have to look into them and see if they are any good etc.

Cheers

[Steven White]

I'm trying to figure out exactly what you're saying on the output of the Black Magic Intensity. My interest in the card would be to capture full 1920x1080 4:2:2 video from a smaller camcorder like the Canon HV20.

If the Black Magic codec has more artefacting than Cineform, it's worthless unless it's significantly better than HDV and DVCPRO-HD... is it? Cineform's wavelet codec has an advantage over the MJPEG users, since it won't show DCT compression artefacts. That doesn't mean there isn't some image softening going on, but it's much harder to detect.

I guess my question is this:
Is it possible to capture uncompressed 1920x1080 4:2:2 with the card and record it to a RAID 0 array? Once this is accomplished, is it possible to convert the files to another codec such as Cineform via an application like After Effects or HDlink?

-Steve

[Richard Leadbetter]

You would need a very fast RAID-0 array for that, but yes it is possible as Blackmagic supply their own uncompressed codec.

Why you would want to do this when you are going to convert to CineForm though is a mystery. Why not use HDLink and capture directly into CFHD?

[Steven White]

Now that I realize I can do that with AspectHD it's golden.

The only problem is that without an upgrade to Prospect, I'm stuck with 1440x1080 as opposed the full-raster 1920 that's coming out of an HDMI port. Particularly since the Intensity is sampling it out at 1920x1080 4:2:2.

I'm still curious though - how does the BlackMagic codec compare to DVCPRO-HD and HDV?

-Steve

[David Newman]

Hopefully Richard will jump on the the MJPEG codec quality, but here is his original observations http://www.dvinfo.net/conf/showpost....56&postcount=1
MJPEG can't stand up against wavelet, it might do OK against HDV and slightly worse against DVCPRO-HD as far as compression artifacts (although DVCPRO-HD will sub-sample to 1280x1080.)

Note: Aspect HD v5 will be getting a codec upgrade from the Prospect HD engine. All the codec will now be running the same core, which is a win for more quality across the board. Aspect HD v5 is still 1440x1080 8-bit I/O, yet the internals are getting an upgrade which will improve quality.

[Richard Leadbetter]

I don't use HDV at all in my workflow so can't comment on that. I've a little experience with DVCPRO-HD (enough to remind me of all the advantages of CineForm!) and Blackmagic's MJPEG codec might offer increased resolution but the artefacts are more easily noticeable IMHO. For non-challenging content, I'm sure MJPEG will suffice. However, I just can't reconcile getting a pristine digital input and then degrading it for no good reason when CineForm retains practically everything.

At the risk of sounding like a CineForm cheerleader, the offer to upgrade to Prospect for $400 is excellent. I'm sure David will correct me if I'm wrong, but not only will you get 1920x1080 capture options, you'll also get 10-bit upconverting which will yield bonuses in post. There's a huge quality advantage we're getting with HDMI, and any software that maximises that should be jumped upon IMO :)

[Steven White]

Oh Richard, thou art so forgiven. I too could be accused of being a Cineform cheerleader on more than one occasion. As an acquisition, intermediate and mastering codec, Cineform is like a dream come true. I've been a fanboy since AspectHD 3.2 (actually, you can still find my unsolicited praise on the Cineform site).

Until the consumer camcorders use those extra 2 bits on the HDMI, the 10-bit support in Prospect will be overkill for a consumer such as myself. However I'm already familiar with the benefits of HDR compositing - and I'm longing for the day when all compositing and colour correction is done in 32-bit float in linear colour spaces.

I wish the consumer camcorder market would abandon HDV, AVC-HD, and DVCPRO-HD in favour of Cineform to flash workflows. Maybe with all the quick solid state drives coming out this will happen in a couple of years. Just yesterday I saw a 16 GB USB 2 flash drive. The write speed on that one was too slow, but there are 4 GB drives with write speeds of up to 20 MB/s that should be enough.

My curiosity here is bypassing the HDV compression and going directly to Cineform - and obviously that's possible. When BlackMagic makes an ExpressCard version of the Intensity, I'll be sailing.

-Steve

[David Taylor]

Originally Posted by Steven White

When BlackMagic makes an ExpressCard version of the Intensity, I'll be sailing. -Steve

Yes, we want that Express Card version too.... Anybody listening at Blackmagic?

[Anton Galimzyanov]

When BlackMagic makes an ExpressCard version of the Intensity...

Ahh, that would be A DAY!!!!

[Anmol Mishra]

Can I confirm if you used virtualdub as a frontend to record from the BM Intensity card in your setup ?

Originally Posted by Richard Leadbetter

Hi there,

Much has been made of the free Blackmagic MJPEG codec bundled with the Intensity, so I thought I would give it a go.

I linked up our somewhat specialised video games HD capture hardware with the Blackmagic 8-bit MJPEG VFW codec today in order to compare it against CineForm. It may be an unfair test as our capture software can address the CineForm DirectShow encoder directly and I am unsure whether the BMD codec has a DirectShow version of its encoder, and if it does, how much of an improvement it is. Notes though:

1. The VFW codec wouldn't accept a YUV 4:2:2 input, I had to feed it 24-bit RGB (CineForm will accept both but flies with YUV 4:2:2)
2. A Pentium 4 3.0GHz CPU with HT really struggled to achieve 30fps capture at 720p without dropping frames. Fed YUV 4:2:2, CineForm has no problems on this CPU
3. The codec does appear to be multi-threaded so should do much much better on a strong Core 2 platform

Picture quality then: well, putting uncompressed YUV 4:2:2 next to CineForm, I have to use zoom in Photoshop on a specific still to spot any differences. And even then half the time I'm not sure if I am actually seeing any difference! In motion it definitely lives up to its 'visually perfect' billing.

Blackmagic MJPEG has typical JPEG artefacting, especially around lettering (the usual pixel fuzziness around lettering, for example). On fine detail it's really not that good either while CineForm is practically flawless.

Filesizes then, and here's a real surprise.

One minute of 'not that challenging' video games 720p/30 footage, captured at 24-bit RGB and compressed on the fly with the mathematically lossless Huffyuv codec was dubbed into various codecs by VirtualDub. Results are:

Huffyuv: 2.23GB (double that for completely uncompressed)
CineForm HD (Low Quality Setting/Progressive): 462MB
CineForm HD (Medium Quality Setting/Progressive): 590MB
CineForm HD (High Quality Setting/Progressive): 757MB
Blackmagic MJPEG (there are no quality settings): 513MB

I was under the impression that the bandwidth used by the MJPEG compressor was lower than CineForm, and it is on all but the lowest quality setting - but not by an appreciably useful margin. Certainly not considering the gulf in quality. I think this is a fair like-for-like test too as (and I might be wrong) the CFHD VFW codec as used by VirtualDub only operates in the 8-bit domain, just like the MJPEG one.

I should also point out that the 462MB 'low' quality CineForm HD file still looked considerably better than the MJPEG in lack of artifacting, retention of key detail etc. It's also worth mentioning that video games capture is characterised by an infinite depth of field, sharper edges - all the stuff that makes compression difficult and artifacting easier to spot.

So in every appreciable way (aside from cost), CineForm HD significantly (if not massively) out-performs the MJPEG codec based on my experience.

[Richard Leadbetter]

Yes. But I've not used the codec since it was launched with the Intensity. Are you aware of whether it's been upgraded at all? For example, a selectable quality level/bitrate?