Exported DVC Pro HD file with incorrect aspect ratio when transcoded for HD DVD

[Rafael Amador]

[Michael Gissing] “Strange numbers. Anamorphic 16:9 is 1440 x 1080. True 16:9 is 1920 x 1080 but 1280 x 1080 is weird.”
You are right Michael. I haven’t realized that.
The size is not standard at all.
rafael

http://www.nagavideo.com

[Adam White]

Hey Guys,

Thanks for your input on this.

I carried on plugging away on this today – and discovered that in fact the encoded files DO have the correct aspect ratio. BUT, it was QuickTime Player displaying them incorrectly! If I open the files in any other programme (i.e. VLC, MpegStreamclip) they look fine.

So the files were being encoded correctly, but QuickTime Player was stretching them on playback. I’m calling Apple later on today to get this mess sorted out!

Oh, by the way, as for the 1280 x 1080 resolution, it’s the correct dimensions for the DVC Pro HD codec. DVC Pro isn’t technically TRUE HD as we know it, so it downsamples higher resolutions to give you 1280 x 1080. Just to add it another complexity, these weird dimensions only apply to 60i DVC Pro video, where as anything in 50i has the much more sensible (and familiar!) dimensions of 1440 x 1080.

Thanks again for trying to help out!

Best,
Adam

[Rafael Amador]

[Adam White] “Oh, by the way, as for the 1280 x 1080 resolution, it’s the correct dimensions for the DVC Pro HD codec. DVC Pro isn’t technically TRUE HD as we know it, so it downsamples higher resolutions to give you 1280 x 1080. Just to add it another complexity, these weird dimensions only apply to 60i DVC Pro video, where as anything in 50i has the much more sensible (and familiar!) dimensions of 1440 x 1080. “

No Adam.
Full raster HD is 1920×1080 Square pixels.
DVCproHD, XDCAM HD and HDV, use HD Pixels and the size is 1440×1080.
1280×1080 doesn’t belong to any standard.
Cheers,
rafael

http://www.nagavideo.com

[Adam White]

Rafael,

From an AJA Whitepaper about the DVC Pro HD format;

“DVCProHD works in non-standard raster sizes, with non-square pixels, to create the same 16:9 picture aspect as full raster HD, without storing as much data. This once again helps to keep the data rates and encoding difficulty down, however the sacrifice is in real resolution. In some cases this will be an acceptable trade off, and in some it will not. Specifically this can cause issues for effects and keying work. In place of standard 1920×1080, DVCProHD encodes 1280×1080 or 1440×1080 depending on the frame rate. In place of 1280×720, DVCProHD encoding down samples to 960×720.”
https://www.aja.com/media_folder_web/AJA_whitepaper_DVCProHD_editing.pdf

The film was shot at 29.97fps – so in 60i – thus, the 1280×1080 dimensions. Had it been shot in 50i then the dimensions would have been 1440×1080.

Also, here you can see a list of Panasonic cameras that use the DVC Pro HD format and the resolutions they record in, the highest resolution being 1280 x 1080 (apart from on the HPX3000 and HPX3700) – https://www.negativespaces.com/blog/tables/digital-production-cameras.htm

So 1280 x 1080 does apply – but only to DVC Pro HD 60i content. I guess you could make an argument that because of the slightly lower resolution it’s not TECHNICALLY a true HD format as we know it – but that’s another issue altogether I suppose!

Best,
Adam

[John Pale]

Rafael, you are completely wrong. Adam is correct.

DVCPRO HD is 1280 pixels (for 1080i/59.94) in the NTSC world. Its only 1440 for PAL.

Adam, do not use the HD-DVD presets. They are for HD-DVD…a now defunct format.
Compressor in Final Cut Studio 3 has BluRay templates, which are what should be used if you want to make a HD disc anyone can actually watch.

Quicktime Player, has for a long time had difficulty with anamorphic pixels. This is nothing new. Don’t worry about it.

[Adam White]

Hi John,

Thanks for your input.

I’ve never used (and probably never will again) the HD DVD presets. This particular client asked for a HD DVD (specifically NOT BluRay) to be authored. Personally I would never use this format, but in this line of work the client is king! I still don’t get enough requests for High Definition DVD content to warrant purchasing a BluRay burner – but I’m sure the time will come.

Equally, I’ll try and avoid the DVC Pro codec in the future, too. Maybe it’s just because I’d never used it before, but I didn’t get on great with it. I’m just so used to Apple ProRes now – solid as a rock and just WORKS with FCP and Compressor. I don’t like to use anything different I guess!

Best,
Adam

[Rafael Amador]

[Adam White] “So 1280 x 1080 does apply – but only to DVC Pro HD 60i content. I guess you could make an argument that because of the slightly lower resolution it’s not TECHNICALLY a true HD format as we know it – but that’s another issue altogether I suppose! “
No arguments at all.
I had no idea of this size (not existing in PAL) and as I can see in the FC presets, its apply not only to 1080i60, but also to 1080p24 and 1080p30. Something new learnt. I thought that all the “HD Pixels’ formats were working at 1440×1080.
Cheers,
rafael

http://www.nagavideo.com