The Art of Compression and Encoding

[Subhadip Sen]

Absolutely, I agree. I think we can cover a lot of ground from the most accessible of solutions (AME, Compressor, etc) to the more advanced, high end tools people are using. I think it will all be helpful. Here are some screen shots of X264 implementation in MPEGStreamclip. My guess is it's exactly what you used. Like I said, these controls are probably not as advanced as some other tools, and therefore may not be the ideal choice for everyone.

Agreed. Beyond the default tools (AME, Compressor etc) I think any X264 frontend with the default presets is a good place to start. MPEG Streamclip is certainly adequate for this purpose. Are you using the latest beta?

[Peter Mosiman]

Hell, a better example, how are apple trailers as good as they look when they're a measly 8.5mbit/s or whatever?

+1 on so many levels. Their stuff always look amazing.

[Steve Sherrick]

Agreed. Beyond the default tools (AME, Compressor etc) I think any X264 frontend with the default presets is a good place to start. MPEG Streamclip is certainly adequate for this purpose. Are you using the latest beta?

I have both, the released version(1.9.2) and the beta(1.9.3b7). As far as I know, I have the latest Mac build of X264 encoder.

Perhaps a good strategy would be to start off with the basics, the entry level tools that allow some level of control and then work our way up from there. I am far from an expert on encoding, so I am hoping people like yourself will jump in and help this thing build momentum and become a valuable resource here.

[Hans von Sonntag]

I just waded through this thread. Good idea btw, Steve.

Besides compression I found scaling to be one of the most determining factor regarding the quality of the result. Here all the usual suspects don't do the best possible job. Telestream's Episode is doing best in this regard, Apple's Compressor is performing below average, IMHO. No wonder really. My Smoke renders under real time for scaling 1080p to SD using all available cores while Apple's compressor is as quick including compression and not using all cores. It's obvious that the software tools are optimized in render speed, not a thing that necessarily helps the quality.

I find that scaling the film down to the target resolution with a trusted tool uncompressed and from there compressing it to h264, WMV etc... is always better then letting the compression tool make the down-res. If you try to convert a pristine 1080p piece with very good text supers to SD MPEG2 for DVD you will notice the difference immediately on the text parts.

Otherwise all the compression tools do the job more or less well and have strengths and weaknesses:

Adobe Media Encoder: It is very good as creating Flash encoded clips and does not need extra plug-ins for this task. For some reason Adobe's Media Encoder creates funky black bars on the side when using one of the DVD presets.

Apple Compressor: It's good at creating ProRes files. Not every compressor can do that this good. Others have funky settings that make my Smoke not liking them. You have to dig pretty deep into the software to fix that.

Telestream Episode: Actually the best of the bunch when scaling is involved. Episode is the only one that allows WMV encoding on the Mac right out of the box. Unlike Adobe Media Encoder it is not linked to an NLE. This can be very helpful.

Bottom-line: On the Mac we have them all installed and use them according to their strengths.

Hans

[Petri Teittinen]

Bloody hell lads, it's "Blu-ray". Get it right. Sorry, a pet peeve of mine.

On-topic: x264 is fantastic. The quality it can squeeze out of ridiculously low bitrates is nothing short of miraculous.

[Wim Verbeek]

Thx Steve, this is a great initiative!

It's hard to find information about all parameters to be able to get the best results.
I have always used h.264 from MainConcept (which is inside the Sorenson Squeeze encoding tool). Reading this thread I think x264 might be a better option (more basic parameters to tweak?).
Within Squeeze's h.264, there's no crf controls available.
I work on windows, mostly DNXHD (Avid) or Uncompressed Animation (AfterEffects) to encode to Bluray/DVD/web.

- waiting for my Scarlet-X -

[MichaelP]

One needs to take into consideration raster size of clip as well into the formula and what the viewer will be using when watching. Mobile devices like phones and tablets have a built in maximum size imposed by the screen. When watching on your computer with screen resolution of 1920 x 1080, then some choices have to made in trade-offs between bit rate, raster size, etc. One must also consider whether the quality of the player resize is good enough for what the end goal is - for example, making smaller than 720p for iPad consumption and letting the player scale. It depends on what the experience will be. For example, I am currently developing a solution for video viewing where I am looking for the best image at the lowest data rate that to fulfill the goal of the project. It does not need to be detail critical but I do need consistency in color. etc. There are lots of considerations when encoding and it is truly an art form, especially when delivering to different channels with different requirements. The industry as whole is working towards the one version in the sky and deliver on the fly to device based on connection - and to some extent that's what a slingbox does which I use a lot in my post work with remote clients for certain processes. There is also a time factor - if I am creating dailies for a quick review or a final piece for delivery, I will cut corners in the dailies version due to turnaround time.

Then there are potential issues between graphic levels and video levels. And what happens when a mobile device is played back to a device that is expecting video levels? Does it scale the black/white levels accordingly? Then you run into the different "looks" modes on home screen and projectors for normal, dynamic, cinema, etc. which all play with levels and tweaking of certain ranges of the color space. If I watch an RGB encoded movie which is 0-255 on such a monitor and cinema mode is on which basically takes the 16-255 levels and makes it full range, you end up with crushed blacks - and that's assuming the monitor was close to being correct overall in the first place. I have no idea what my iPad is calibrated to, and how consistent that is overall.

And of course progressive sources always encode better overall compared to interlace (motion resolution versus data rate), and starting out with a high resolution images engages the concept of "supersampling" when creating images at lower resolution, bit depth data rate, etc. Trailers look so good because they are at 24fps (low frame rate) and progressive - any given data rate will have more quality per frame at 24 compared to 30 or 59.94.

My quick thoughts -


Michael

[Meryem Ersoz]

these guys have done a good job of optimizing Compressor and it's only 39 bucks. I get good results.

http://www.compressorpack.com

would love to have something similar developed for Adobe, now that we are all migrating.

this is another very good alternative: http://www.dvkitchen.com/features/encoder.html -

DV Kitchen is fast, which makes it easy to run experiments with various compression selections, until you get a result you like.

These are both simple and inexpensive.

Also - DivX is becoming a decent alternative - the problem has always been narrow acceptance, but I think that's changing.

More good links on the subject...

http://www.compression.ru/video/code...4_2005_en.html

http://www.doom9.org/index.html?/codecs-final-105-1.htm

[Michel Rabe]

Resizing is definately part of compression quality.
What bothers me is that in Photoshop you can choose from 5 different resizing algorithms. There's no such option in Premiere Pro (or AE). There were times I resized in Photoshop just to know that the optimal algorithm was being used.
Right now my latest info was that, working in Premiere, creating a new sequence and resizing the source within the timeline and then export is supposed to give best results, but there are different opinions out there.

As for x264, how do you guys update it? Do I have to remove older versions or even packs that contain it like ffmpeg when updating?

[M Most]

There are lots of considerations when encoding and it is truly an art form, especially when delivering to different channels with different requirements.

There is also the fact that one size does not fit all, and one set of settings can't possibly be optimal for every scene in a show. That's why scene by scene programmed compression is what's done for DVD and BluRay releases. And that compression is controlled by a compressionist, a person whose sole job is to determine proper optimal compression settings on a per scene basis based on the total "bit budget," or the required final file size. That's one reason why studio level DVD's have always looked a lot better than those produced by individuals using single compression settings, regardless of the compression engine. When there are fewer compromises, there are better results.