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"Why does my favorite old movie look like shit? I want 1100 words by Thursday" "Because they're compressing it too much. There are parameters in all compress

by mapt 11y ago

"Why does my favorite old movie look like shit? I want 1100 words by Thursday" "Because they're compressing it too much. There are parameters in all compression formats where you can make the files bigger or smaller, and they're making the movie too small, so a videophile will notice differences. Resolution is the largest of these parameters, and it corresponds to actual hardware, but it's not the only one. They're cheating you out of accurate movement in order to make their data processing easier." "I do not understand the words that are coming out of your mouth because I have an art degree. 1100 words. Emotive language. Thursday." ----- You have a problem with a transfer? Reduce the amount of compression to well beyond the level your focus group can detect, and increase the resolution. Don't talk about “the random scatter of photosensitive molecules in the emulsion creates an overall softness and shimmer,” because data is data, and sufficient amounts of data can represent that scatter just fine. From MPEG-2 to H.265, video format advances have reduced data needs to maybe 20% of what they used to be, while from 480p to 8K, resolution improvements have increased data needs by a factor of 108x. Businesses have failed to cope honestly: They're selling the higher resolution but compressing more heavily so it looks just like it used to look, or giving only token data allowances so 1080p is given 50% more data than 480p rather than the 575% it needs in order that a 480p inset in that larger picture has the identical performance as the lower resolution stream would. And that is why Youtube looks like shit, and that is why film transfers are still not performing at the level we want.

golergka 11y ago
I'm not sure why are you talking about H.265 at all. DCP format uses JPEG 2000 compression for video, and it doesn't use 1080p: the screen size are from 1998×1080 to 4096×2160.
- mapt 11y ago
  h.265 is a generic example of the state of the art in video compression. The distinction between 1080x1998 vs 1080x1920 is negligible. The point stands without the minutia. When you double the resolution, the amount of data you're representing goes up by a factor of four. Businesses who double the resolution of their streams have not raised their data rates by a factor of four or even a factor of two, and the progress in encoding, while significant, has not been remotely sufficient. We're compressing more heavily than ever before because for some reason marketting can sell resolution at the edge of theoretical human perception, but not a fat data pipe well within human perceptual range.
  - ska 11y ago
    You're not wrong, but you have to be a bit careful with this line of reasoning when talking about compression, particularly: 4x the content in terms of pixels is not necessarily 4x the information content, and the latter is the real issue. Also worth thinking about. With transferring old film stock to digital, you have a potentially long pipeline of which compression is just that last step. I'd hesitate to blame all visual distortion (relative to the original) on compression without looking at it carefully.
mapt 11y ago
The standard for HD television in the US, ATSC A/53, provides for: "The maximum bitrate of the MPEG-2 video stream is exactly 19.4 Mbit/s for broadcast television, and exactly 38.8 Mbit/s for the "high-data-rate" mode (e.g., cable television). (The practical limit is somewhat lower, since the MPEG-2 video stream must fit inside a transport stream, with overhead, sent out at 19.3927... Mbit/s for broadcast.)" 38.8 megabits per second is 291 megabytes per minute, or 17.5 gigabytes per hour. You're more likely to be watching something that's compressed an order of magnitude more, because businesses think they can cheap out on it without consequences. Here's Youtube's bitrates: http://www.sciencemedianetwork.org/Blog/20130624_YouTube_bitrates http://www.sciencemedianetwork.org/Blog/20130624_YouTube_bit... . Transferring analog content lossfully at similar resolution is another issue - if the VHS tape has about 240p equivalent resolution, and you transfer it with perfect fidelity to an uncompressed 240p digital stream, you're losing a lot of information, because those dots don't line up perfectly with those pixels, instead smearing out over multiple pixels. Instead of thinking 'equivalent resolution', think Nyquist frequency.
- joezydeco 11y ago
  If you've ever seen OTA HD at full bandwidth, it's beautiful. Sadly, nobody ever sees it because either a) the broadcaster has added 7 subchannels and/or b) almost everyone is watching on cable or satellite and the provider has compressed it all to hell to fit their own transport. I think Fox is the rare broadcaster in my city that doesn't subchannel and puts sporting events on in full bandwidth mode.
madaxe_again 11y ago
It's not entirely about compression - some "remasters" have been de-noised (i.e. no more grain - which in my opinion (and it is opinion) loses some of the atmosphere of a film (hell, if grain is unimportant, why do so many games have shaders which add it?)), some are run through a sharpen filter to deal with out of focus scenes and to "improve" the image quality, and so-forth - so it's not so much about compression as it is about other subjective "improvements" made to the transfer. An example of something which has been done wonderfully, again in my opinion, is last year's restoration of "The Cabinet of Dr. Caligari". Interestingly, they re-added the original tints to the remaster, as what's not commonly known is that many "black and white" films were projected through a coloured glass slide, in order to either give the entire scene a hue, or even to make the ground red/brown and the sky blue.
- mapt 11y ago
  "Interestingly, they re-added the original tints to the remaster, as what's not commonly known is that many "black and white" films were projected through a coloured glass slide, in order to either give the entire scene a hue, or even to make the ground red/brown and the sky blue." I'd always wondered where Top Gear gained its impressive cinematic style - they must have happened upon a treasure trove of those two-color filters, and asked what it would feel like applied digitally to every other scene with the saturation pumped up.
  - mcguire 11y ago
    And then they went crazy with it, to the point where you were watching a purported car review that successfully concealed the color of the vehicle by the application of art. It became distracting. But not as distracting as Top Gear's urge to rotate the camera to emphasize the slope when a car is going up or down hill. Or HGTV's urge to run segments containing fireplaces in reverse.
  - madaxe_again 11y ago
    You can still buy such things - I use them in photography - See Cokin, for instance - it's their entire business. http://www.cokin.co.uk/ http://www.cokin.co.uk/
austinjp 11y ago
Is "I do not understand [you] because I have an art degree" the same as "you would benefit from learning how to communicate effectively with a non-technical audience"? Probably not, but they seem to be conflated. That's not to defend poor journalism. But it is important to notice where willful ignorance or aggressive blaming damages communications.
ars 11y ago
Compressed data bandwidth for a video does not scale with resolution. i.e. quadrupling the number of pixels does not require quadruple the bandwidth for the same quality. I believe it goes up by the square root. So quadrupling the number of pixels needs only double the bandwidth. There are several reasons for this, one of which is that motion compensation is constant - it doesn't much matter what the resolution is, it takes the same amount of data to encode motion. Another is that as resolution goes up there are more opportunities for similar areas in the image which compress well.

by mapt 11y ago

golergka 11y ago

I'm not sure why are you talking about H.265 at all. DCP format uses JPEG 2000 compression for video, and it doesn't use 1080p: the screen size are from 1998×1080 to 4096×2160.

mapt 11y ago
h.265 is a generic example of the state of the art in video compression. The distinction between 1080x1998 vs 1080x1920 is negligible. The point stands without the minutia. When you double the resolution, the amount of data you're representing goes up by a factor of four. Businesses who double the resolution of their streams have not raised their data rates by a factor of four or even a factor of two, and the progress in encoding, while significant, has not been remotely sufficient. We're compressing more heavily than ever before because for some reason marketting can sell resolution at the edge of theoretical human perception, but not a fat data pipe well within human perceptual range.
- ska 11y ago
  You're not wrong, but you have to be a bit careful with this line of reasoning when talking about compression, particularly: 4x the content in terms of pixels is not necessarily 4x the information content, and the latter is the real issue. Also worth thinking about. With transferring old film stock to digital, you have a potentially long pipeline of which compression is just that last step. I'd hesitate to blame all visual distortion (relative to the original) on compression without looking at it carefully.

mapt 11y ago

The standard for HD television in the US, ATSC A/53, provides for: "The maximum bitrate of the MPEG-2 video stream is exactly 19.4 Mbit/s for broadcast television, and exactly 38.8 Mbit/s for the "high-data-rate" mode (e.g., cable television). (The practical limit is somewhat lower, since the MPEG-2 video stream must fit inside a transport stream, with overhead, sent out at 19.3927... Mbit/s for broadcast.)" 38.8 megabits per second is 291 megabytes per minute, or 17.5 gigabytes per hour. You're more likely to be watching something that's compressed an order of magnitude more, because businesses think they can cheap out on it without consequences. Here's Youtube's bitrates: http://www.sciencemedianetwork.org/Blog/20130624_YouTube_bitrates http://www.sciencemedianetwork.org/Blog/20130624_YouTube_bit... . Transferring analog content lossfully at similar resolution is another issue - if the VHS tape has about 240p equivalent resolution, and you transfer it with perfect fidelity to an uncompressed 240p digital stream, you're losing a lot of information, because those dots don't line up perfectly with those pixels, instead smearing out over multiple pixels. Instead of thinking 'equivalent resolution', think Nyquist frequency.

joezydeco 11y ago
If you've ever seen OTA HD at full bandwidth, it's beautiful. Sadly, nobody ever sees it because either a) the broadcaster has added 7 subchannels and/or b) almost everyone is watching on cable or satellite and the provider has compressed it all to hell to fit their own transport. I think Fox is the rare broadcaster in my city that doesn't subchannel and puts sporting events on in full bandwidth mode.

madaxe_again 11y ago

It's not entirely about compression - some "remasters" have been de-noised (i.e. no more grain - which in my opinion (and it is opinion) loses some of the atmosphere of a film (hell, if grain is unimportant, why do so many games have shaders which add it?)), some are run through a sharpen filter to deal with out of focus scenes and to "improve" the image quality, and so-forth - so it's not so much about compression as it is about other subjective "improvements" made to the transfer. An example of something which has been done wonderfully, again in my opinion, is last year's restoration of "The Cabinet of Dr. Caligari". Interestingly, they re-added the original tints to the remaster, as what's not commonly known is that many "black and white" films were projected through a coloured glass slide, in order to either give the entire scene a hue, or even to make the ground red/brown and the sky blue.

mapt 11y ago
"Interestingly, they re-added the original tints to the remaster, as what's not commonly known is that many "black and white" films were projected through a coloured glass slide, in order to either give the entire scene a hue, or even to make the ground red/brown and the sky blue." I'd always wondered where Top Gear gained its impressive cinematic style - they must have happened upon a treasure trove of those two-color filters, and asked what it would feel like applied digitally to every other scene with the saturation pumped up.
- mcguire 11y ago
  And then they went crazy with it, to the point where you were watching a purported car review that successfully concealed the color of the vehicle by the application of art. It became distracting. But not as distracting as Top Gear's urge to rotate the camera to emphasize the slope when a car is going up or down hill. Or HGTV's urge to run segments containing fireplaces in reverse.
- madaxe_again 11y ago
  You can still buy such things - I use them in photography - See Cokin, for instance - it's their entire business. http://www.cokin.co.uk/ http://www.cokin.co.uk/

austinjp 11y ago

Is "I do not understand [you] because I have an art degree" the same as "you would benefit from learning how to communicate effectively with a non-technical audience"? Probably not, but they seem to be conflated. That's not to defend poor journalism. But it is important to notice where willful ignorance or aggressive blaming damages communications.

ars 11y ago

Compressed data bandwidth for a video does not scale with resolution. i.e. quadrupling the number of pixels does not require quadruple the bandwidth for the same quality. I believe it goes up by the square root. So quadrupling the number of pixels needs only double the bandwidth. There are several reasons for this, one of which is that motion compensation is constant - it doesn't much matter what the resolution is, it takes the same amount of data to encode motion. Another is that as resolution goes up there are more opportunities for similar areas in the image which compress well.