AC3 embedded Cineform AVI

[Edgar Pitt]

We are looking at high quality screening options at a local digital theater for our feature film.

We are considering creating a HDCAM SR master and renting a deck to playback at the theater, but this is an expensive and cumbersome process.

Since we are using Cineform as our digital intermediate, would it not make sense to stay in this format and color space for projection? If so, the next question is how do we sync our 5.1 Dolby mix in AC3 format?

Are there any advantages at all for going the SR route?

Thanks.

Edgar

[David Newman]

You can absolutely use CineForm for theatre projection, many have, we have. You can put an AC3 audio track into an AVI, I just haven't tried myself. There are tools that will re-splice an existing AVI video track with an external audio track. You might be able to use VirtualDub (I have used with other WAV or PCM audio tracks, just not with AC3.)

[Edgar Pitt]

Thanks David. I will give that software a try.

Can you recommend a software player for playback on Windows? Something other than Media Player?

Edgar

[David Taylor]

Edgar, we've used Media Player Classic to drive a digital projector when using DVI. You might see if that meets your needs.

[Edgar Pitt]

Thanks guys. Would the quality be lower if we used DVI? We have a Quadro FX 4600, but this does not allow for 10-bit output.

Would something like this work better for playback:

Aja Xena HS SD/HD PCI Card - eBay (item 190265079859 end time Nov-13-08 22:00:00 PST)

Would this also allow for embedded 6 channel audio?

Many Thanks.

Edgar

[David Taylor]

Playout through DVI is 8 bit whereas you can have 10-bit playout through AJA.

But...playout from Media Player Classic through DVI should be dead easy, whereas you'll have some work to do to build a player for the Xena card. You might check with AJA to see if they have some suggestions for a player, but it will have to be a DirectShow based player to play the CineForm files.

BTW, we've projected through DVI to various 2K projectors numerous times including a Christie and it looks AWESOME! When we did the Christie projection it was using StEM footage (codec-buster footage), and was for some golden eye tests. Everybody thought it looked great. I suspect you'd have the same reaction.

If you have a contact at a theater, ask them if you can bring your PC down to the theater before they open and connect it to the DVI input on the projector. You can judge quality for yourself. You'll still have to solve the multi-channel audio problem. That we haven't specifically had to solve for the projection work we've done.

[Edgar Pitt]

Are there any advantages or disadvanges for projecting in 8-bit versus 10-bit with Cineform files?

If we use 10-bit projection via HD-SDI, will the output be cleaner (less noise)? Or is it the opposite - that 10-bit will "enhance" the noise by showing finer detail?

We are looking at renting one of the following projectors for the event:

Barco FLM HD18 Projector
Panasonic PT-DW10000U HD Projector

Thanks.

Edgar

[David Taylor]

Edgar, using 10 bits is most important going through your post workflow so you don't introduce banding during the various processes of stretching your images. I won't argue that 10-bit projection is technically better than 8-bit projection. But my experience is that unless you're looking at very specific still images, it is unlikely anyone will notice the difference. Again, I'd recommend that you do the tests for yourself through DVI. If you like what you see then the work necessary is much reduce compared to HD-SDI with multiple channel audio.

[Edgar Pitt]

Thanks David. We will setup a test at the theater. They have a Christie X3, which is lower resolution, but it will allow us to test our Dolby audio files as well.

I have posted on an AJA forum about the six channel audio, and I will post back here with an update.

Edgar

[Mike McCarthy]

If you use Premiere Pro as your playback software, then you can use the SDI out on the AJA HS, and you can get 6 channel uncompressed audio, without having to embed an AC3 file in an AVI. (Just use a 5.1 sequence in Premiere, and import a six channel wav)
We use Premiere with an SDI card to feed our theater all the time.

The other totally different option would be to use a BluRay player with HDMI, which will give you 1080p and 5.1 sound. The content will have been H264 compressed before it hits the screen is the only problem.

[Richard Leadbetter]

Indeed, plus you're looking at a drop from CineForm 4:4:4 or 4:2:2 down to 4:2:0.

[Edgar Pitt]

Mike - Thanks a lot for that valuable information. We will test this setup at the local theater in a few days.

Edgar

[Edgar Pitt]

When using Premiere playing through the Xena HS, should the audio be embeded in the HD-SDI signal or outputed through the AES inputs to XLR?

If the audio is embedded in the HD-SDI, do we need a device that outputs to a format that the theater can input into their system? Something like this:

http://www.aja.com/html/products_converters_HD10AM.html

Many Thanks.

Edgar

[Mike McCarthy]

The HS will output Audio to the AES outputs, but I am not sure about the embedded SDI. I haven't used an HS in a long time. The Xena LH card supports embedding audio over SDI, but I am not certain if Premiere/Prospect supports that. Which cards support embedded SDI audio in Prospect is something you will want to confirm with Cineform. If you need analog outputs, you will need a convertor for sure.