Codec Levels

I know there are gazillions of codecs so i am am not asking for everything.

However, is the only difference in codecs, aspect and color space?

I have been trying to figure out what would be a top ten in terms of codec quality. Some of you may say that this is not possible but there some reoccurrence of codec that i hear often.

dv - dvcpro - hdv - 720p - 1080i&p - uncompressed 8&10 bit - animation - XD - photo jpeg - apple intermediate and prores422.

If these codecs were on a top 10 list for quality were would they rank?
I am not sure if photo jpeg is better than dv but i know most folks say that DV sucks peanuts.

BTW, I DID A GOOGLE SEARCH but can not find an answer. I have been dropping dv into several different sequence settings to see what the difference might be. I only see a difference when grading in the color app.

""" What you do with what you have, is more important than what you could do, with what you don't have."

> > > Knowledge + Action = Wisdom - J. Corbett 1992 """"

I am not even going to take a swipe at assigning a rank to codecs. Each one has been designed for a different use.

As a rule of thumb, newer is better. When a codec is designed, often there are hardware limitations and bandwidth restrictions that the designer is working with. For example, MPEG-1 was designed to be used on systems with early CD drives that had a fixed bandwidth limit. There are also software "tools" to be considered. The understanding of the math of compression is a lot better today than it was in the early 90's.

Some codecs are designed to be easy to edit. ProRes for example or DNxHD. Others are tough to edit but ideal for web distribution. MPEG-2 is used for broadcast TV and DVD. Not the best looking or lowest bit rate maybe, but the only thing that can be decoded by about 20 gazillion consumer devices.

So, you see, the only way to rank codecs from best to worst is to first consider what the process is that you are trying to accomplish.

-Vance

Well it would make more sense to ask what it is you're working on and how you intend to deliver it. If you shot something on a DV camera, there's nothing wrong with editing in DV. If you are creating original animation in the computer, uncompressed or ProRes are wise alternatives because they add less compression. However, if your eventual destination is back on DV tape, it will need to be encoded to DV ultimately. So- what are you trying to do?

Noah

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720p and 1080i are NOT codecs. They are frame sizes.

Why must you rank them? As Vance said, there are reasons for choosing one codec over the other.

Are you bored?


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You have to know the difference between frame sizes and codecs to rank them...which nobody does. Differnt codecs = different jobs.

When life gives you dilemmas...make dilemmanade.

JCorbett
" have been dropping dv into several different sequence settings to see what the difference might be. I only see a difference when grading in the color app."

Sorry I missed this bit on the first read. As a rule of thumb you never will get an image better than the most compressed codec the image has been subjected too. So if you shoot in DV, dropping it in an uncompressed timeline will not improve the image quality. When you have tossed out the detail and added the artifacts they are there forever.

The exception to this, as you have seen, is what happens in downstream processing. If you take that DV into an your uncompressed 10 bit timeline and pass it to Color, you enable Color to take advantage of the extra bits to subtly shade your footage. However, when you output again to DV tape most of that advantage is lost on re-compression to DV.

The other place this is applicable is in the graphics area. Let's say our very talented colleague Mr. Morelli is making an open for our show, shot in DV. He is going to use some of our footage, but is going to be also using bold color and text. He may well chose a codec like Animation or perhaps even work uncompressed.

When that file is returned to us we could continue in the codec he used. We then put our DV material on the timeline after the open. After a render, our material looks no better BUT his looks no worse. Then that can be output in various codecs for distribution, each looking a bit better for not stomping on Joey's work with a DV codec.

I am not saying that this is absolutely the best way to work, but it might be, depending on the needs of the project.

As long as we're on the subject, a lot of people seem to miss this one: Animation is not a good compressor to use on video. It's an RGB compressor, which means Animation shots brought into Final Cut are subjected to the same RGB-YUV dynamic-range mapping that RGB stills are. This can throw off your gamma significantly if you're not careful.

Pretty much the only reason to use Animation is if you need a Quicktime movie with an alpha channel. For instance, yesterday I created an animated bug in After Effects. I had the choice of rendering it out as separate fill and travel matte Quicktimes, or just rendering it out as a single RGBA Animation Quicktime. I went with Animation, because Final Cut detects and automatically applies the matte from the alpha channel, making superimposition trivial.

But be aware that using Animation on live-action footage in the YUV color space is a dicey proposition.

Thats a really good point Jeff.

A lot of people use animation as an end all for quality but shifting YUV to RGB is a big deal. That's not a conversion to take lightly if you're trying match footage or exact colors.

OK as long as we are experiencing a bit of topic drift, I am going to use Jeff's post as a stair step to one of my favorite soapboxes.

Why oh why when Apple created ProRes did they NOT allow for an optional alpha channel? Really world, in order to carry alpha do we have to use an image sequence or use a codec that was designed when Lincoln was president?

Is it too TOO much to ask for a modern codec that knows we sometimes composite things in the world of visual communications?

OK I'm done.

EXCELLENT QUESTION. About a year ago when I first got into a ProRes workflow I was baffled as to why there's no facility for ProRes to include an alpha channel. Sure, it would inflate the file ridiculously, turning it into 4:2:2:4, but it would be nice if it had the option, at least.

Track mattes are so twentieth century.

I disagree on the alpha channel- it has no place in a codec meant for heavy video usage and mastering. There's no alpha in DV, DVCPROHD, HDV, XDCAM EX, etc. In fact the only 'video' codec I know of in regular use with an alpha is the animation codec. Besides- any regular VFX guru will tell you they seldom use video formats for animation but almost always image sequences such as .PSD, TGA, or TIF where an alpha channel is much more prevalent.

Noah

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Author, RED: The Ultimate Guide to Using the Revolutionary Camera available now at: [www.amazon.com].
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Just to get my 2 cents into the discussion. Usually I would say the lesser the compression, the better. But Grafixjoe hit the nail on the head. They all serve a purpose- from end user codecs, acquisition codecs, digital intermediates, etc.

>He may well chose a codec like Animation or perhaps even work uncompressed.

There's a slight difference between the two. Animation is capable of being a lossless 8 bit RGB codec. Uncompressed is due to its nature, a chroma subsampled format, even if lossy data compression isn't used.

>I am not sure if photo jpeg is better than dv but i know most folks say that DV sucks peanuts.

P-jpeg compression is designed for stills/progressive video. DV, on the other hand, has had the reputation of being the format most commonly used by indie film makers and film students the world over, due to the low cost of DV cameras, the ease of the workflow, and the relatively low storage required for the format.



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> There's no alpha in DV, DVCPROHD, HDV, XDCAM EX, etc.

DNxHD supports an alpha channel, not that I've tried keying off it...



www.strypesinpost.com

Quote

Besides- any regular VFX guru will tell you they seldom use video formats for animation but almost always image sequences such as .PSD, TGA, or TIF where an alpha channel is much more prevalent.

I'm no "regular VFX guru" but I will disagree with that. I hardly ever use image sequences. 99.9999% of the time I render out an Animation file w/ Straight Alpha Channel. There's nothing worse than one of those files in a sequence going missing.

I, too, am baffled that ProRes does not support an Alpha Channel. Shocked. Bamboozled. Freaked out. You get the picture.

When life gives you dilemmas...make dilemmanade.

Quote
Noah
However, if your eventual destination is back on DV tape, it will need to be encoded to DV ultimately. So- what are you trying to do?

When i did the Color training it was suggested that i drop dv into TLs with better color space. But then as you say i am out to a mepg2 codec. I have noticed slight differences in encoding when using higher codecs as input.

Yesterday, I did my very 1st all cpu generated video with Motion. Nothing but psd, stills, text gens and motion filters. I only used fcp to merge the audio.

so my workflow was...... psd > motion (animation codec) > soundtrack > fcp (uncomped 8bit) > compressor (mpeg2) > dvdsp (sd dvd).

In FCP i tried 3 different codecs; uncomped 8 and 10 and dvcpro50. I settled on the uncomped 8. (2min TL = 5.6g)

The dvd looked good. Then last week i was trying all kinds of codecs on these 2 45sec dv and dvcpro50 clip in fcp then exporting to QTSC to compare the differences. I opened the file in color to see the the luma and chroma levels better. The uncomped stuff seemed to have the highest chroma.
I sent them thru compressor for upresing also.

Remember, that i was not comparing the dv clip to the dvcpro50 hd clip. Rather, i was looking at the dv to see what levels i could take it to before it becomes super ugly. The same for the dvcpro50.

I tried to take as many notes as i could but i still wasn't able to figure out which codecs was demanding more or less. So, I posted this to get a better understanding on where the codecs ranked in the dv upres process, color space and when i am asking to much of dv.

The dvcpro50 held up in most situations regardless of the application of codec i believed to be better or larger in file size at the same frame size / aspect.

I was left with the question of rankings.

Also, other than frame size / aspect and color space i couldn't figure out what the codec has in it to separate one from the other. This is necessary i think to understand how to set a workflow for specific results.

""" What you do with what you have, is more important than what you could do, with what you don't have."

> > > Knowledge + Action = Wisdom - J. Corbett 1992 """"

"Color space" ≠ "chroma subsampling pattern."

Thus ends my pet peeve gripe of the moment.

JCorbett
"Also, other than frame size / aspect and color space i couldn't figure out what the codec has in it to separate one from the other. "

Wow is that a big topic. I would recommend again a good text on the fundamentals of compression.

Just as a for instance, there are about 10 different tools that can be used in MPEG-2 compression. All forms use DCT transform, and most use RLE. Some use bi-directional motion compensation and some use no motion comp at all.

I apologize for using terms that I am not defining, but I am not trying to be descriptive here, but rather suggest that this is a BIG topic. I have been studying it on and off for more than a decade. I read text books on the topic, magazine articles, web pages. I have attended numerous SMPTE conventions. I still can't really get my arms around it. I am far from the sharpest knife in the draw, and barely have enough math to balance my check book. The few folks I have met or listen to lecture on the topic are PhD mathematicians.

That is not to imply that you need that PhD to chose the proper codec for any given gig. Some experimentation and experience are all that is needed to do that.

NoahK:
"Besides- any regular VFX guru will tell you they seldom use video formats for animation but almost always image sequences such as .PSD, TGA, or TIF where an alpha channel is much more prevalent. "

This may be a cart before the horse thing. I bet that if a good video codec that carried alpha was available it would quickly become the standard for transferring files from graphics programs to editors.

BTW have you ever tried to use an image sequence in FCP? You can set your import to a 1 frame duration to pull in the files, but it WAY chokes FCP. WAY.

VPiccin thanks. I was just thinking that there was a good better best thing in this. I see it more of a usage thing.

I guess there is not a way of knowing how far up or down the scale you can go.

Thanks All.

""" What you do with what you have, is more important than what you could do, with what you don't have."

> > > Knowledge + Action = Wisdom - J. Corbett 1992 """"

>BTW have you ever tried to use an image sequence in FCP? You can set your import to a 1 frame
>duration to pull in the files, but it WAY chokes FCP. WAY.

Import image sequence in QT Pro. I avoid importing image sequences directly to FCP like the plague.



www.strypesinpost.com

in the fwiw category, i seem to remember that all the Avid quicktime codecs support an alpha channel ... even their DV codec

Quote
andy
all the Avid quicktime codecs support an alpha channel ... even their DV codec

Strong capability that fcp doesn't have. Maybe, fcs3 will. I need to revisit Avid in its new version.

""" What you do with what you have, is more important than what you could do, with what you don't have."

> > > Knowledge + Action = Wisdom - J. Corbett 1992 """"

Because it's a video codec not a graphics codec. Nothing to stop them bringing out ProRes444 with alpha channel support in the future.

Martin Baker
[www.digital-heaven.co.uk]
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I like the way you think, Marty

When life gives you dilemmas...make dilemmanade.