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The End of Video Coding?

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Re: The End of Video Coding?

#101

Post by squeaky-clean »

cc-d wrote: post #52
izacus wrote: post #39

Earlier quoted context omitted.

Yep, but YouTube doesn't require full DRM support.

Requiring protocol level DRM to be included in video/music streaming technologies has always baffled me. What's the point? Even with theoretically perfect protocol level DRM, the consumer eventually has to be able to see/hear the protected content. If the frames of the video are displayed on screen, and the audio played through the speakers, the output can be recorded and preserved, period. Do the people in charge of…

I bought an HDMI cloner box the same day Netflix announced they were adding this DRM.

I actually haven't even taken it out of the box yet. But it just feels good to know their DRM is pointless.

Re: The End of Video Coding?

#102

Post by Tarq0n »

ktta wrote: post #82
derf_ wrote: post #51

Earlier quoted context omitted.

There are a couple of things that make Netflix somewhat unique. 1) They have a fairly limited catalog (contrast with the constant ingestion of new content by Youtube, for example) 2) The cheapest way for them to ensure they have sufficient capacity to handle peak loads leaves them with a lot of extra compute during non-peak times. That excess compute is essentially free.

>That excess compute is essentially free. Since they host on AWS, wouldn't they just scale down during non-peak times and save money?

Netflix has an internal spot market for compute, letting them use their reserved instances somewhat optimally.

Re: The End of Video Coding?

#103

Post by verall »

wilun wrote: post #92
shawn wrote: post #77

Earlier quoted context omitted.

It was a stab at irony. True, but the video is already subsampled. That's how it was able to be uploaded at 1080p at all, since the source video is 8k. So 8k vs 1080p shouldn't make any difference on monitors less than M-by-1080 resolution.

The video is typically subsampled at encoding at capture resolution, but it is also subsampled at other encoding resolutions. Because the whole point of subsampling is to be taken into account during encoding, and encoding itself needs not to vary depending on whether the source was downscaled or not. So video codecs most of the time work with some subsampled chroma components. So your encoded 1080p might be able to…

It's not just that the eye is less sensitive to chroma.

Although your 4:2:0 subsampled 1080p video only has 540x960 pixels with chroma information, the decoder should be doing chroma upsampling, and unless its a super simple algorithm it should be doing basic edge detecting and fixing the blurry edges chroma subsampling is known to cause. I posit that even with training, without getting very very close to your screen you wouldn't be able to tell if the source material was subsampled 4:2:0, 4:2:2, or 4:4:4.

The truth is that generally people DO subjectively prefer high resolution source material that has been downscaled. Downscaling can clean up aliasing and soften over-sharp edges.

People who watch anime sometimes upscale video beyond their screen size with a neuron-based algorithm, and then downscale to their screen size, in order to achieve subjectively better image quality. This is even considering that almost all 1080p anime is produced in 720p and then upscaled in post-processing!

Re: The End of Video Coding?

#104

Post by robocat »

cc-d wrote: post #52
izacus wrote: post #39

Earlier quoted context omitted.

Yep, but YouTube doesn't require full DRM support.

Requiring protocol level DRM to be included in video/music streaming technologies has always baffled me. What's the point? Even with theoretically perfect protocol level DRM, the consumer eventually has to be able to see/hear the protected content. If the frames of the video are displayed on screen, and the audio played through the speakers, the output can be recorded and preserved, period. Do the people in charge of…

Recording the analog output has a lower quality than the original stream for 3 main reasons:

1. Marketing and psychology: Viewers want to believe they are viewing the original, not a degraded copy.

2. Unfaithful copy: Analog output and analog input introduce errors. LCDs use a variety of tricks to improve resolution such as spacial and temporal dithering. Also you can't use a normal camera to record a monitor because of aliasing (of pixels and non-genlocked frame rates).

3. Encoding noise. The encoding of the original is based on the higher quality original, and carefully optimised for the least visual artifacts. Any re-encoding also has to deal with noise introduced by the copying process, and with the noise introduced by the original encoding. This noise noticeably reduces the quality of a copy.

Re: The End of Video Coding?

#105

Post by 0x09 »

MayeulC wrote: post #100

Are there transmission schemes that can transfer multiple independent streams that add up for better quality? It could be streams containing information about smaller subblocs, etc. If you take a fourrier transform, the more coefficients you include, the more faithful the reproduction is. Splitting the quality level into multiple independent streams could have multiple advantages : - better use of Multicast, as viewe…

This is known as scalable coding and has been included as an extension or profile in at least every ISO and ITU standard since MPEG-2, see for example https://en.wikipedia.org/wiki/Scalable_Video_Coding (this article seems to be specific to H.264)

Re: The End of Video Coding?

#107

Post by da_chicken »

carbonatedmilk wrote: post #2

Pull quote: We run compute on the cloud and have no real-time requirements. I was asked by the Chair, “How much complexity increase is acceptable?” I was not prepared for the question, so did some quick math in my mind estimating an upper bound and said “At the worst case 100X.” The room of about a hundred video standardization experts burst out laughing. I looked at the Chair perplexed, and he says, “Don’t worry the…

I'm someone with an intermediate level of coding experience, but I have no idea what exactly is meant here by "encoding complexity". What's the difference between 3X and 100X? What's the encoding complexity of h.264 vs MPEG-2? Is it just saying that they're OK with the encoding algorithm taking 100 times as much processing power or taking 100 times as many processor cycles to compress a given data stream?

Re: The End of Video Coding?

#108

Post by da_chicken »

cc-d wrote: post #52
izacus wrote: post #39

Earlier quoted context omitted.

Yep, but YouTube doesn't require full DRM support.

Requiring protocol level DRM to be included in video/music streaming technologies has always baffled me. What's the point? Even with theoretically perfect protocol level DRM, the consumer eventually has to be able to see/hear the protected content. If the frames of the video are displayed on screen, and the audio played through the speakers, the output can be recorded and preserved, period. Do the people in charge of…

> Requiring protocol level DRM to be included in video/music streaming technologies has always baffled me.

> What's the point?

It's the same reason you put a lock on the door to your house. You know the lock is easily bypassed by tools. The windows are easily broken. The door can probably be easily forced open. But you still lock the door when you leave in the morning.

Locks are about keeping casual theives as honest people. DRM is about keeping casual pirates as honest customers. It's about making it just difficult enough to copy that most people will consider it not worth the bother. It's about saying, "You must be this determined to break the law."

Re: The End of Video Coding?

#109

Post by therein »

robocat wrote: post #104
cc-d wrote: post #52

Earlier quoted context omitted.

Requiring protocol level DRM to be included in video/music streaming technologies has always baffled me. What's the point? Even with theoretically perfect protocol level DRM, the consumer eventually has to be able to see/hear the protected content. If the frames of the video are displayed on screen, and the audio played through the speakers, the output can be recorded and preserved, period. Do the people in charge of…

Recording the analog output has a lower quality than the original stream for 3 main reasons: 1. Marketing and psychology: Viewers want to believe they are viewing the original, not a degraded copy. 2. Unfaithful copy: Analog output and analog input introduce errors. LCDs use a variety of tricks to improve resolution such as spacial and temporal dithering. Also you can't use a normal camera to record a monitor because…

If anyone is wondering, this whole concept referred to as the analog hole. [1]

[1] https://en.wikipedia.org/wiki/Analog_hole

Re: The End of Video Coding?

#110

Post by walrus01 »

majewsky wrote: post #86
ktta wrote: post #82

Earlier quoted context omitted.

>That excess compute is essentially free. Since they host on AWS, wouldn't they just scale down during non-peak times and save money?

The AWS-hosted part is not the CDN afaik, which will probably make up the vast majority of their infrastructure.

Speaking as an ISP: Netflix traffic comes from the Netflix ASN and peering session. Their globally distributed CDN/caching/video file storage servers are not on AWS to the best of my knowledge. Netflix traffic does not come from our peering with Amazon's ASN.
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