Filming at 1080 and downconverting to SD (Workflow help!)

proximity

proximity

Well-known member
Hey there, I hope someone has run into this.

When I bought the HVX, I didn't actually want to deliver HD products, and I still don't. But filming at DVCPROHD100 (which allows phenomenal colorspace, gamma depth etc.) compared to regular DVPAL makes a lot of sence, because I should be able to convert it down to SD, in for example the DVCPRO50 format and still exceed "regular" DV limits. - I tried this yesterday, just to check out how the workflow is. I wantet to check my CPUs speed, Quicktimes settings etc. But I where very suprised about the low quality.

I'm a PAL user, and have been capturing Extreme Martial Arts footage at 1080/50i, because thats all Final Cut Pro supports (in HD PAL). But, i'm actually working towards the most film realistic look I can achieve. But, I actually want to do SD, with very good colorspace in SD, pref. with progressive frames. (Naturally i'm deinterlacing the footage to convert it to 25p (or 24p) instead of 50i). But, when I did some pretty basic converting tests Quicktime, I found that the DVCPROHD100 (1080/50i) --> to --> DVCPRO50 (SD) looks competly horrible. Of course SD can't justify the detail of the original HD footage, but I even remember getting better results with H.264 than this.

So I tested that some more, and sure enough, H.264 (Full quality in SD def.) actually makes better looking footage than DVCPRO50 (SD). This is completly backwards because H.264 is not a workflow format, it's an enduser format. Which is not in any way suited for working with in FCP. The detail I get when converting to H.264 is sharp and crips, whilst DVCPRO50 looks very very smudgy and poor.

Can anyone please suggest what my workflow should look like to get the best possible quality?

- Proximity
 
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proximity said:
Hey there, I hope someone has run into this.

When I bought the HVX, I didn't actually want to deliver HD products, and I still don't. But filming at DVCPROHD100 (which allows phenomenal colorspace, gamma depth etc.) compared to regular DVPAL makes a lot of sence, because I should be able to convert it down to SD, in for example the DVCPRO50 format and still exceed "regular" DV limits. - I tried this yesterday, just to check out how the workflow is. I wantet to check my CPUs speed, Quicktimes settings etc. But I where very suprised about the low quality.

I'm a PAL user, and have been capturing Extreme Martial Arts footage at 1080/50i, because thats all Final Cut Pro supports (in HD PAL). But, i'm actually working towards the most film realistic look I can achieve. But, I actually want to do SD, with very good colorspace in SD, pref. with progressive frames. (Naturally i'm deinterlacing the footage to convert it to 25p (or 24p) instead of 50i). But, when I did some pretty basic converting tests Quicktime, I found that the DVCPROHD100 (1080/50i) --> to --> DVCPRO50 (SD) looks competly horrible. Of course SD can't justify the detail of the original HD footage, but I even remember getting better results with H.264 than this.

So I tested that some more, and sure enough, H.264 (Full quality in SD def.) actually makes better looking footage than DVCPRO50 (SD). This is completly backwards because H.264 is not a workflow format, it's an enduser format. Which is not in any way suited for working with in FCP. The detail I get when converting to H.264 is sharp and crips, whilst DVCPRO50 looks very very smudgy and poor.

Can anyone please suggest what my workflow should look like to get the best possible quality?

- Proximity
Click to expand...



I think H.264 is a very nice codec regardless of enduser, or workflow format.

DVCPRO50, seems to have varying degrees of compression from what I have for choices when using that format. Maybe you are on the lower setting.

In Edius, I can be in DVCPRO and pick many options. In fact, I am not sure if the HQ is higher quality, or the uncompressed.

Turn your options to the highest setting, and try again. It's probably the way you are making the file instead of the format it is in.

That being said, I would not be surprised if a good H.264 codec looked better than dvcpro50. It's newer, and does very nice things in small files.

It just might not hold up under more than one recompression like a workflow format will.
 
Maybe this is a stupid question, but please explain me why you want to record in 1080p if your final product will be in sd?
I would understand to use 720 for the framerates, but if you wount ever use the hd, then it would be better to shoot in dvcpro 50, where you got less compession then in hd and have immediatly the "highets quality" of dvcpro 50.

This is a serious question, cause i am also interested in getting the highest results in sd, but from my idea there will be the point where you lose the efforts of mor resolution of hd in downconverting to sd.(specially if it is a bad quality conversion..)
 
Hd Pal ?????????????????

Hd Pal ?????????????????

Proximity,

I always understood the Definition of PAL to be:

PAL = (Phase Alternating Line) A color TV standard that was developed in Germany. It broadcasts 25 interlaced frames per second (50 half frames per second) at 625 lines of resolution. Brazil uses PAL M, which broadcasts 30 fps. PAL is used throughout Europe and China as well as in various African, South American and Middle Eastern countries. PAL's color signals are maintained automatically, and the TV set does not have a user-adjustable hue control.

Quoting Barry Green "HD is neither PAL nor NTSC, it is HD. It is a format in and of its own self."

Skuzzle

ps. Thanks for your sarcasm.
 
hvx_germanboy said:
Maybe this is a stupid question, but please explain me why you want to record in 1080p if your final product will be in sd?
I would understand to use 720 for the framerates, but if you wount ever use the hd, then it would be better to shoot in dvcpro 50, where you got less compession then in hd and have immediatly the "highets quality" of dvcpro 50.

This is a serious question, cause i am also interested in getting the highest results in sd, but from my idea there will be the point where you lose the efforts of mor resolution of hd in downconverting to sd.(specially if it is a bad quality conversion..)
Click to expand...


Well, that's just because I don't use P2 cards, I do direct capture to a laptop running Final Cut Pro. And since I'm in Norway, using a HVX-200E, i'm shooting in "PAL mode". which is 1080 over 50i,

But to answer you question. When delivering a video via the web at H.264, the video looks 10000 times better if it's a compressed 4:2:2 1080 file (compressed into a smaller H.264 format) than if you just compress "regular" HD.
 
proximity said:
I'm a PAL user, and have been capturing Extreme Martial Arts footage at 1080/50i But, I actually want to do SD, with very good colorspace in SD, pref. with progressive frames
(Naturally i'm deinterlacing the footage to convert it to 25p (or 24p) instead of 50i).
Click to expand...

G'day.
It's hard to tell what might be happening with only the information that you have provided, but for starters, why are you capturing interlaced then deinterlacing if you say you would prefer progressive? If you are converting to a progressive format then why aren't you capturing to 1080p in the first place?
Also just because you have captured into a DVC PRO format doesn't mean you have to stay in the DVC PRO format when you downconvert to SD.
 
proximity said:
Well, that's just because I don't use P2 cards, I do direct capture to a laptop running Final Cut Pro. And since I'm in Norway, using a HVX-200E, i'm shooting in "PAL mode". which is 1080 over 50i,

But to answer you question. When delivering a video via the web at H.264, the video looks 10000 times better if it's a compressed 4:2:2 1080 file (compressed into a smaller H.264 format) than if you just compress "regular" HD.
Click to expand...
Just a few notes:

1080p25 captures perfectly in FCP over firewire.
When you switch from 50i to 25p on the HVX only the CCD/DSP is switched from interlace to progressive. The stream format is always 1080i50, so it works perfectly with FCP. No need to deinterlace.

As others have noted PAL refers to an analog SD broadcasting standard with regards to resolution, color coding, frequency etc.
Calling something PAL 1080 is plain wrong. 576i50 is the digital format description for the PAL signal without the analog color encoding. So actually it would even be a little wrong to call a digital only 576i50 signal for PAL as it does not include the analog encoding which is what the phase alternating is about.
You can never broadcast any HD 1080 or 720 in PAL. Hope I don't come across as someone a jerk, but it really matters :-)
 
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proximity said:
I did some pretty basic converting tests Quicktime, I found that the DVCPROHD100 (1080/50i) --> to --> DVCPRO50 (SD) looks competly horrible. Of course SD can't justify the detail of the original HD footage, but I even remember getting better results with H.264 than this.

So I tested that some more, and sure enough, H.264 (Full quality in SD def.) actually makes better looking footage than DVCPRO50 (SD).
Click to expand...

Are you comparing the results in the quicktime player?
If so be sure to check the "always play in high quality" checkbox in the quicktime player preference window, otherwise DVCPRO50 will by default play back in half resolution on the mac monitor. H264 does not have this feature. DV codecs and DVCPRO codecs have this feature built into the codec to be able to do multistreams on slow computers. By dropping some of the decoding steps it only uses 1/4 of the CPU it would take to playback at full quality.
 
Anders Holck said:
Just a few notes:

1080p25 captures perfectly in FCP over firewire.
When you switch from 50i to 25p on the HVX only the CCD/DSP is switched from interlace to progressive. The stream format is always 1080i50, so it works perfectly with FCP. No need to deinterlace.

As others have noted PAL refers to an analog SD broadcasting standard with regards to resolution, color coding, frequency etc.
Calling something PAL 1080 is plain wrong. 576i50 is the digital format description for the PAL signal without the analog color encoding. So actually it would even be a little wrong to call a digital only 576i50 signal for PAL as it does not include the analog encoding which is what the phase alternating is about.
Click to expand...

Quite right, basically, besides the different variations of HD pertaining to scan lines (1080 and 720) and wether progressive or interlaced, there are the different flavors of frame rates. 60, 30 or 24 usually used in NTSC countries and 50 or 25 found in PAL countries.

Now about downconverting, indeed you do not need to stick to DVCpro. What are you exporting to, DV, BetaSP, DigiBeta or some other tape format; or are you compressing directly to DVD ? I have obtained best results going to SD 10bits uncompressed. From there I export via SDI (with a Blackmagic Decklink HD card) to DigiBeta tape. As a side note, I have been disapointed by the Blackmagic software live downconversion and obtained better results doing the downconversion in FCP. It's a lot of rendering and 1.5 GB per minute however. You'll also need good drives that are not fragmented, start with a clean drive. If you're going straight to DVD, I believe compressor can downconvert on compression. I use BitVice (which rules) and downconversion is available in v1.7 just released, however make sure to change the resizing algorythm to something else than QT, the default.

To answer those that question why shoot in HD. The quality difference is clearly superior, and you have the HD footage available if and when the demand is there.

Cheers,
Damien
 
Anders Holck said:
Are you comparing the results in the quicktime player?
If so be sure to check the "always play in high quality" checkbox in the quicktime player preference window, otherwise DVCPRO50 will by default play back in half resolution on the mac monitor. H264 does not have this feature. DV codecs and DVCPRO codecs have this feature built into the codec to be able to do multistreams on slow computers. By dropping some of the decoding steps it only uses 1/4 of the CPU it would take to playback at full quality.
Click to expand...

I didn't think of that at all. Thanks, (good thinking :p )

- Proximity
 
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