Cleaning 5D/7D/T2i Footage

Hi Douglas,

Just came across this post and visited your website, as I was unaware of its existence. I have found some of it quite informative with my current level of understand of encoding and video file outputs. However, I was unable to find some things covered that have current ly been perplexing me and am passionately pursuing an answer.

With a large influence to transcode your cameras native video files for ease of editing and file size, I am confused as to how that original already compressed native video file can be converted to a lossy format, then brought into the NLE, then exported from there into yet another (lossy?) format and look as good or better then the original native video file. All of the conversion suggest a loss of information to me, information which is unabel to be retrieved by the later video's formats. Doesn't that loss of information come with the price of quality loss of the image? Yet the final video is smaller in size. Would the quality not be greatest having stuck with the original video file?

What I am ultimately after is finding a solid work flow that fits my cameras, my editing software and my delivery. Im using Premiere CS5, an h.264 .MOV DSLR camera as well as an AVCHD camcorder.

I am in desperate need of further understandings of codec's, what is most popularly used in the consumer and pro world and what is all available at this time. Im looking for in depth tech talk, like in the Zacuto Camera shoot out I saw recently where the creators are discussing RGB, color space, BPC and am very eager to wrap my head around all of it.
 
Tylers86 said:
With a large influence to transcode your cameras native video files for ease of editing and file size, I am confused as to how that original already compressed native video file can be converted to a lossy format, then brought into the NLE, then exported from there into yet another (lossy?) format and look as good or better then the original native video file. All of the conversion suggest a loss of information to me, information which is unabel to be retrieved by the later video's formats. Doesn't that loss of information come with the price of quality loss of the image? Yet the final video is smaller in size. Would the quality not be greatest having stuck with the original video file?
Click to expand...

A very common method for professional compressionists to get a better picture out of a compressed format is to do a chroma upsample method and then store it in a video format that is better. The end result is a file that is better quality than your original. Some methods of chroma upsampling are very slow, this is a process that has to be batched ahead of time of the edit.

De-noising is very helpful for video sharing sites, since it helps with the compressibility when it comes to low bitrates.

Compression experts aren't just "using the right settings" on the compression utility. That's like 10% of our work :)
 
Tylers86 said:
With a large influence to transcode your cameras native video files for ease of editing and file size, I am confused as to how that original already compressed native video file can be converted to a lossy format, then brought into the NLE, then exported from there into yet another (lossy?) format and look as good or better then the original native video file. All of the conversion suggest a loss of information to me, information which is unabel to be retrieved by the later video's formats. Doesn't that loss of information come with the price of quality loss of the image? Yet the final video is smaller in size. Would the quality not be greatest having stuck with the original video file?
Click to expand...
This is a big misconception in the field of video processing. On an objective and technical level, it is impossible to make a video better, but you can make it perceptually better. For example, there's currently a huge debate over the use of digital noise reduction on many Blu-ray discs, and indeed, there are cases where it is simply abused, and the picture quality suffers greatly. However, pretty much all remasters that you've seen (and even new movies) are cleaned up at least slightly in the grain department, as it appears nicer, presents a more consistent image across shots, etc.

It's not that we're making the image better in the end, it's that we're doing our best to not let it become further destroyed in compression, and noise is something that compression schemes absolutely hate. Removing/reducing it means that lossy compression appears less lossy. A lot of work in compression, as Demistate seems to be implying, is a matter of good taste, balance, and knowing how to use your tools. Often times (almost always), I will literally copy/paste settings from one video to the other, but that's only after figuring out appropriate settings for the first video.

Good luck.
 
Thank you gent's, I always appreciate good words. So I am correct about recompressing leading to a loss overall? But, using available tools, knowledge of them and applying your creativity to your work through selectivly choosing your recompression based on the look you want and where the video will end up. Right?

I guess it's that word, "re" compressing; implying a forced loss with every render. One after the other just being a copy of a copy for however many renders ithere are from the original file. This is what has made me consider just working with native h.264 files within CS5 as my computer seems to keep up with it. Apparntly, however, not transcoding into a non-delivery(h.264, AVCHD), more editing friendly codec is taking away from the flexibility and quality of post processing.

So is the answer to always recompress your original file and then import that to your editing software? As you said Demistate, a common method of compressionists to get better picture out of a compressed format is to render it to a better format out of your editor. Is that "better" format totally dependant on each project you work on? Is it common to go back to an h.264 codec, or is bringing it out of its editing codec going to wash away all the PP you just did?
 
It only means using an archival codec. There are many lossless codecs out there that have zero impact on picture quality, or at least high-bitrate lossy codecs (read: most high end recorded formats) that are practically lossless because of such utter bitrate saturation. Even if it is not visually noticeable, pre-existing compression affects future compression, hence it is ideal to use a high bitrate or lossless codec for mastering, before exporting to any other format.
 
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