Is it confirmed DiscoveryHD accepts XDCAM?

[Brian Mills]

I have heard that XDCAMHD does not have the same 15% content restriction as HDV for DiscoveryHD,,,can someone confirm this? I am producing a pilot I'd like to shop around and I can save a grip working in XDCAM over HDCAM for my workflow.

Has anyone had experience shooting 100% XDCAMHD for any other HD network?

Thanks in advance....

[Ivan Snoeckx]

Take a look at this PDF document.

Discovery HD Specifications

Greetings!

[Brian Mills]

Thanks Ivan!

Now I'm new to XDCAM so no one please get upset by this question: XDCAMHD is NOT considered HDV at 35mbs, right? (since they use similar GOP MPEG2 encoding, its a little confusing)

[Ivan Snoeckx]

XDCAM HD is not the HDV format in 18, 25 or 35 mbps mode. It is called MPEG-HD.

[Brian Mills]

Originally Posted by Ivan Snoeckx

XDCAM HD is not the HDV format in 18, 25 or 35 mbps mode. It is called MPEG-HD.

Thanks for the clarification!

[Alister Chapman]

XDCAM HD at 35Mb uses a variable bit rate codec as opposed to HDV's constant bit rate codec. This allows XDCAM to adjust how the data is allocated to each frame, thus frame that need extra bandwidth get it. This results in a much more efficient use of the data and thus far fewer artifacts and better performance overall.

[Bob Willis]

and XDCAM HD at 25mbps is a constant bit rate that is very much the same thing as HDV.

[Greg Boston]

Originally Posted by Bob Willis

and XDCAM HD at 25mbps is a constant bit rate that is very much the same thing as HDV.

Nope, still not the same as HDV because of the higher quality front end on a camera. It is able to put a lot better image into the MPEG encoder even at 25mb CBR. It may be spec'd the same, but the video from the F350/330 would still look better upon close inspection. Larger chips are a big part of the reason allowing for wider dynamic range and lower noise.

Also, from the audio side, the XDCAM HD produces 4 channel uncompressed audio in all modes of shooting, whereas HDV is using MPEG compression on the audio. That's not to say that HDV audio doesn't sound very good when handled correctly.

-gb-

[Bob Willis]

and "the video specs" for XDCAM HD at 25mbps is a constant bit rate that is very much the same thing as HDV.

[Mike Watson]

The same, only different.

So no, they're not the same. Read the specs, Bob.

Incidentally, there is not a "very much" the same. .There is merely the same and not. This... is not.

[Chris Hurd]

They are not at all the same. The common bit rate is meaningless in this regard.

We cleared up this misconception back in April: http://www.dvinfo.net/conf/showthread.php?t=90898

[Bob Willis]

I have read the specs and I use both HDV and XDCAM HD. I am only refering to the recording specs, not the difference in camera lenses or chip size. I see no information in the link you provided to the contrary, Chris.

There is no question that the 35mbps of XDCAM is a different animal, but at 25mbps and a constant bit rate, it shows the same issues as HDV. Don't get me wrong, I find the HDV footage from a Sony Z1 to be quite amazing. It will also cut quite well with the XDCAM footage (from the F350) if it is handled properly.

The 2 cameras have been a great compliment to each other. I do look forward to the new Sony EX when it is released, as it will allow an even better match and can record at 24p and variable frame rates.

[Matthew Pugerude]

Originally Posted by Bob Willis

It will also cut quite well with the XDCAM footage (from the F350) if it is handled properly.

I see this statement a lot I have used the setup a lot also. But I have not edited the footage that I have shot with this setup. So when people say when you set the Z1 up correctly it will cut together well. What is this magic setup that people are talking about? Because most of the time we just leave the Z1 at its default settings and go. I have not heard anything from the post house that the footage is drastically different as a matter of fact they have not said anything to me about the footage at all. But that is a whole other story in itself.

[Vaughan Wood]

I'm following this discussion with interest.

Can someone clear something up for me?

Is the audio sampling rate is not taken up in the quoted figures of HDV's 25 CBR mbps. compared to XDCam's 35 VBR mbps?

Not knowing the precise figures, I would have thought that 4 uncompressed audio tracks would take up lot of mbits more than two tracks of MPEG audio.

Or is it all video compression that is talked about here, with audio added on, or is audio included in the figures, if so, how much room does the 4 channels PCM take up?

Cheers all,

Vaughan

[Kevin Shaw]

Originally Posted by Ivan Snoeckx

Take a look at this PDF document.

Discovery HD Specifications

Looks like a key fact here is that XDCAM HD source footage is only accepted in the 35 Mbps recording mode, which makes sense. Also interesting that footage from the Panasonic HVX200 is accepted with the same restrictions as HDV, which shows that the overall quality of a camera is at least as important as the recording format it uses.