3 ms·

ATSC 3 uses HVEC (instead of MPEG2 like ATSC 1) so the quality will shoot way up assuming encryption doesn't spoil it for everyone.

dylan604 3y ago
I don't see how encryption would affect the image quality. Obviously not being able to decode the stream makes things difficult, but that has nothing to do with the codec used to compress the video.
- cogman10 3y ago
  Most video streams degrade gracefully when data is corrupted. Losing a byte or two is (generally) not that big of a deal. Encryption turns every dataloss into something catastrophic. Now, instead of 1 byte lost, you are talking about 1 mb lost (or whatever the size of the encryption chunks are). That becomes especially bad as codecs get more bandwidth friendly. That 1mb can represent a lot of data, which ultimately gets corrupted until the next keyframe flows through. You can sort of think of it in terms of a bitmap vs jpeg. If you corrupt 40 bytes in a 1mb bitmap, no problem, it will still mostly look like the original image. However, if you turn that bitmap into a 30kb jpeg and corrupt 40 bytes, now that's a much more significant amount of the information changed.
  - bobdvb 3y ago
    The block cipher used on broadcast doesn't have a big impact. People have been doing encryption on pay TV broadcasting for decades. There's also plenty of error correction, often 25% of the broadcast feed data is ECC.
    - cogman10 3y ago
      Like I said, it expands the amount of data lost when corruption does happen. You can't have 1 bit off. And, due to the nature of interference, it's generally a block of bytes that end up corrupted. Encrypted pay tv exists (in the form of satellite transmissions) but there, interference is minimized by having a geosynchronous satellite high in the air directly beaming a signal. Only bad weather interferes. Further, because it's being beamed from a single source (rather than multiple towers around an area). you can point your dish directly at the satellite to get a relatively perfect directional connection. Other signals, the sun, power lines, etc don't generally interfere because you are concentrating a focused signal. That math all changes when talking about receiving multiple terrestrial signals with a non-directional antenna. If you've watched satellite tv, you know that whenever a storm rolls through it becomes unwatchable. There's not really any sort of graceful degradation, it's either a perfect signal or a blank screen with "no signal". SOMETIMES you might see giant swaths of green blocks or whatever if the corruption is just right, but generally speaking it's all or nothing. Meanwhile, I get relatively weak signals from a couple of weak OTA stations. For the most part, the images are perfectly passable.

dylan604 3y ago

I don't see how encryption would affect the image quality. Obviously not being able to decode the stream makes things difficult, but that has nothing to do with the codec used to compress the video.

cogman10 3y ago
Most video streams degrade gracefully when data is corrupted. Losing a byte or two is (generally) not that big of a deal. Encryption turns every dataloss into something catastrophic. Now, instead of 1 byte lost, you are talking about 1 mb lost (or whatever the size of the encryption chunks are). That becomes especially bad as codecs get more bandwidth friendly. That 1mb can represent a lot of data, which ultimately gets corrupted until the next keyframe flows through. You can sort of think of it in terms of a bitmap vs jpeg. If you corrupt 40 bytes in a 1mb bitmap, no problem, it will still mostly look like the original image. However, if you turn that bitmap into a 30kb jpeg and corrupt 40 bytes, now that's a much more significant amount of the information changed.
- bobdvb 3y ago
  The block cipher used on broadcast doesn't have a big impact. People have been doing encryption on pay TV broadcasting for decades. There's also plenty of error correction, often 25% of the broadcast feed data is ECC.
  - cogman10 3y ago
    Like I said, it expands the amount of data lost when corruption does happen. You can't have 1 bit off. And, due to the nature of interference, it's generally a block of bytes that end up corrupted. Encrypted pay tv exists (in the form of satellite transmissions) but there, interference is minimized by having a geosynchronous satellite high in the air directly beaming a signal. Only bad weather interferes. Further, because it's being beamed from a single source (rather than multiple towers around an area). you can point your dish directly at the satellite to get a relatively perfect directional connection. Other signals, the sun, power lines, etc don't generally interfere because you are concentrating a focused signal. That math all changes when talking about receiving multiple terrestrial signals with a non-directional antenna. If you've watched satellite tv, you know that whenever a storm rolls through it becomes unwatchable. There's not really any sort of graceful degradation, it's either a perfect signal or a blank screen with "no signal". SOMETIMES you might see giant swaths of green blocks or whatever if the corruption is just right, but generally speaking it's all or nothing. Meanwhile, I get relatively weak signals from a couple of weak OTA stations. For the most part, the images are perfectly passable.