H264 to HEVC without quality loss?

[bobhays]

So like anyone who has a video collection I have a lot of H264 videos. Since basically all new processors, gpus,  phones, etc are supporting HEVC I think it's time to start making my library HEVC.

 

The thing is all blu-ray rips are in H264, is there a way to convert to HEVC without losing quality? I assume the process is something like decompressing the H264 and compressing it with HEVC which would lose quality since both formats are lossy. Is there another way? 

[Electronics Wizardy]

h265 is mostly lossy, so no, but you won't notice it.

 

Id wait a year or two for the standards to get better. There still isn't great support and encoders will be better in a few years.

[TrigrH]

unless its anime i wouldn't bother as the file size decrease wont warrant the effort.

[mariushm]

The x265 open source encoder is not mature enough to give you great quality all the time. With the same settings, it could produce a great encoding of a particular movie, yet produce a crap encoding on another movie, you still have to tweak some parameters from video to video if you want good quality rips.

Hardware hevc encoders (like the ones in video cards) are optimized to be very fast, but don't use all the features hevc has, so the quality is not the best. You'd have to increase the bitrate quite a bit to get the quality you already get with h264, so it makes no sense unless you really need hevc content.

 

Overall, if you had the original bluray and you'd make a rip, with the best settings in x265 you'd get a file that's around 70% the size of a rip encoded in h264. It's not worth spending 10-14 hours per encode just to save 500MB - 1 GB per video and your portable devices should already support h264 content quite well already.

 

And re-compression from already compressed h264 to HEVC will introduce additional losses, it's like compressing from MP3 to AAC ... each codec has its own way to save bits when shrinking something down to a size, so when compressing to hevc, you'll lose some more quality. It's not worth it. 

 

Also keep in mind that hevc decoding (even when done in hardware) will use more energy, so a phone or some laptop will play less minutes of hevc video compared to h264 videos.

 

[Vitalius]

I've done a ton of testing on this. 

Blu-ray rips that are lossless can be around 12-20GB in size with x264. Converting to x265/HEVC at 1,500 Kb/s using Handbrake with 2-pass encoding, I can get those files to around 1.2-2GB without noticing a loss in quality. 

If the normal Handbrake won't work for you for some reason (I've noticed it breaking on some files), try a nightly build as that sometimes fixes it for me. 

YMMV. HEVC is best at long content. I go from 12 GB -> 1.2 GB regularly for movies, but for episodes that are regular length (say 23-27 minutes), I go from something like 350MB to around 330MB. Not worth the effort, but those aren't (effectively) lossless. (Effectively) lossless x264 (assume huge bit rate) for such an episode can put it at the 1.1-2GB range which after HEVCing at 1,500 Kb/s puts it at around 400-500 MB (since it has higher quality to begin with).

Note that the above CPU setting was Medium. HEVC doesn't support hardware acceleration via GPUs and such. 

[mariushm]

vitalius, you probably have lousy monitors or lousy eyesight.  Don't know who would say  a "butchered" 1.2 GB movie is "visually lossless".

 

And modern GPUs have HEVC encoders and decoders built-in, for the example the RX series from AMD and the Pascal series. Even the RX 460 which is not that expensive can encode 1080p HEVC faster than real time, but of course quality won't match software encoding.

See http://forum.doom9.org/showthread.php?p=1778777#post1778777 as an example

[Vitalius]

15 minutes ago, mariushm said:

vitalius, you probably have lousy monitors or lousy eyesight.  Don't know who would say  a "butchered" 1.2 GB movie is "visually lossless".

Don't know what you are talking about. 

I stated x264 episodes of a show (for example) that are 23-27 minutes long can be 1-2GB in size if encoded at a high enough bit rate that it's effectively lossless. If I set the bit rate to 10,000 Kb/s it's effectively, or getting pretty close to, lossless.

A 27 minute video that is 2GB is around 9,800 Kb/s once audio is considered. 

You used quotes and I didn't even say that. Use brackets for paraphrasing (i.e. [I can't read] - mariushm)

That is interesting information regarding x265 encoding with the GPU. I'm curious to try it.

[pyrojoe34]

29 minutes ago, Vitalius said:

I've done a ton of testing on this. 

Blu-ray rips that are lossless can be around 12-20GB in size with x264. Converting to x265/HEVC at 1,500 Kb/s using Handbrake with 2-pass encoding, I can get those files to around 1.2-2GB without noticing a loss in quality. 

If the normal Handbrake won't work for you for some reason (I've noticed it breaking on some files), try a nightly build as that sometimes fixes it for me. 

YMMV. HEVC is best at long content. I go from 12 GB -> 1.2 GB regularly for movies, but for episodes that are regular length (say 23-27 minutes), I go from something like 350MB to around 330MB. Not worth the effort, but those aren't (effectively) lossless. (Effectively) lossless x264 (assume huge bit rate) for such an episode can put it at the 1.1-2GB range which after HEVCing at 1,500 Kb/s puts it at around 400-500 MB (since it has higher quality to begin with).

Note that the above CPU setting was Medium. HEVC doesn't support hardware acceleration via GPUs and such. 

That's not possible, no amount of clever coding or codec changes will allow a 1080p video to be at 1.5Mbps without significant loss of quality. I could see maybe 10Mbps assuming a very clever compression algorithm, 8 bit and low framerates, very little motion, and the person doesn't know what to look for (but even that low seems very unlikely to be unnoticeable to most people). Even at 720 or 480p 1.5Mbps creates a lot of artifacts.

[Vitalius]

9 minutes ago, pyrojoe34 said:

That's not possible, no amount of clever coding or codec changes will allow a 1080p video to be at 1.5Mbps without significant loss of quality. I could see maybe 10Mbps assuming a very clever compression algorithm, 8 bit and low framerates, very little motion, and the person doesn't know what to look for. Even at 720p 1.5Mbps creates a lot of artifacts.

Well that's not at all what I've experienced. 

HEVC does stand for High Efficiency Video Coding which is a compression standard. 

I can tell you that before, when movies are 8-12 GB for me (as an example), you can see a lot of grain in it, but after HEVC at 1,500 Kb/s (which is what I push all my media as), the areas where there was grain are smoothed out. Now I don't mean people's skin looks like porcelain dolls or like they have tons of makeup on. 

I think such things are positive and make a movie look nicer. Motion seems fine. Dark scenes seem fine. 

This is with 1080p movies.

I don't know what to tell you other than what I've experienced. 

This is unrelated but useful information: http://www.streamingmedia.com/Articles/Editorial/Featured-Articles/The-Great-UHD-Codec-Debate-Googles-VP9-Vs.-HEVC-H.265-103577.aspx

[mariushm]

Of course they're smoothed out at 1.5mbps, as that's one way to reduce the need for bitrate, grain is hard to compress. But that grain often is part of the movie, it's meant to be there, it's often meant to  work on you without realizing, to set a mood of a movie, along with color palette.

 

 

hevc 1.5mbps can produce acceptable results for example for shows with scenes where the camera is mostly static, and with few transitions. Thinking of Friends or other such TV shows.

[pyrojoe34]

1 minute ago, Vitalius said:

Well that's not at all what I've experienced. 

HEVC does stand for High Efficiency Video Coding which is a compression standard. 

I can tell you that before, when movies are 8-12 GB for me (as an example), you can see a lot of grain in it, but after HEVC, the areas where there was grain are smoothed out. I think such things are positive and make a movie look nicer. Motion seems fine. Dark scenes seem fine. 

I don't know what to tell you other than what I've experienced. 

This is unrelated but useful information: http://www.streamingmedia.com/Articles/Editorial/Featured-Articles/The-Great-UHD-Codec-Debate-Googles-VP9-Vs.-HEVC-H.265-103577.aspx

If you see something in a video (like grain) that disappears after your convert that video to another codec, that is the loss of information. Unless you mean converting the raw video directly to HEVC vs directly to h.264, but if you're converting a video that is h.264 into HEVC and the video looks any different, you have already lost information. In this one case (the grain) you consider that a positive loss since it appears smoother to you but you are also losing a ton of other information in the process. You can't take a compressed video and increase the quality by converting it to a better codec or higher bitrate, it doesn't work like that, you already lost the data in the first compression.

 

You can test this yourself, take a lossless video or photo and convert it to jpg (if you can't see a difference after one compression then compress it a couple times), then take that compressed photo and convert it back to lossless. The conversion back to lossless will not look any better than the jpg you used to make it, it's not possible.

 

In your case, if you are converting your h.264 to HEVC you are losing information not matter what since HEVC is inherently lossy (just less lossy than older codecs).

[helping]

1 hour ago, pyrojoe34 said:

If you see something in a video (like grain) that disappears after your convert that video to another codec, that is the loss of information. Unless you mean converting the raw video directly to HEVC vs directly to h.264, but if you're converting a video that is h.264 into HEVC and the video looks any different, you have already lost information. In this one case (the grain) you consider that a positive loss since it appears smoother to you but you are also losing a ton of other information in the process. You can't take a compressed video and increase the quality by converting it to a better codec or higher bitrate, it doesn't work like that, you already lost the data in the first compression.

 

You can test this yourself, take a lossless video or photo and convert it to jpg (if you can't see a difference after one compression then compress it a couple times), then take that compressed photo and convert it back to lossless. The conversion back to lossless will not look any better than the jpg you used to make it, it's not possible.

 

In your case, if you are converting your h.264 to HEVC you are losing information not matter what since HEVC is inherently lossy (just less lossy than older codecs).

Are you being intentionally daft or just skimming posts and filling things in as you go?

[pyrojoe34]

22 minutes ago, helping said:

Are you being intentionally daft or just skimming posts and filling things in as you go?

What are you talking about? The guy I replied to is talking about not noticing a loss of quality by converting to 1.5Mbps HEVC which I said was not likely since 1.5Mbps is just not enough to preserve HD video quality regardless of the codec. Then he went on to state that by converting his h.264 bluray rips to HEVC he somehow improved the video quality of the original rips, which is absolutely, literally impossible. The best you can do is not diminish the video quality more by encoding in either lossless or a higher relative bitrate. Any transcoding from one codec to another lossy codec (like HEVC) will reduce the quality by some amount. Saying you increased the quality of a video by transcoding it is not a thing, that's not how data compression works.

[Zodiark1593]

For my Cardcaptor Sakura Blu Ray series, I'm wondering if it would be worthwhile to perform a re-rip and encode with x265 for 1500 kbps. Currently at h.264 with the same bit trate. Only concern is none of my devices save for Nala (desktop) can play h.265 video in hardware, and my phone is confined to software only. 

[rcarteraz]

39 minutes ago, Zodiark1593 said:

For my Cardcaptor Sakura Blu Ray series, I'm wondering if it would be worthwhile to perform a re-rip and encode with x265 for 1500 kbps. Currently at h.264 with the same bit trate. Only concern is none of my devices save for Nala (desktop) can play h.265 video in hardware, and my phone is confined to software only. 

You should never re-encode something that's already been encoded once in my opinion. It loses too much.

[Zodiark1593]

2 hours ago, rcarteraz said:

You should never re-encode something that's already been encoded once in my opinion. It loses too much.

I have the Blu Rays, I can rip them again is what I was mentioning. Not re-encoding the stuff already on the hard drive. 

 

I know enough about A/V to know multiple lossy encodes is a horrible idea. 

[rcarteraz]

1 hour ago, Zodiark1593 said:

I have the Blu Rays, I can rip them again is what I was mentioning. Not re-encoding the stuff already on the hard drive. 

 

I know enough about A/V to know multiple lossy encodes is a horrible idea. 

Well if you have the blurays to rip then you could but as mentioned by several others it would be best to wait on HEVC.

[Zodiark1593]

13 minutes ago, rcarteraz said:

Well if you have the blurays to rip then you could but as mentioned by several others it would be best to wait on HEVC.

Last I tried x265 1500 kbps, the quality wasn't much better when trying a Blu Ray of Guardians of the galaxy than using x264, 1500 kbps,though encode times went up dramatically. Wonder how anime would look though. I'll probably try an episode, and maybe post some screenshots.

[bobhays]

20 hours ago, mariushm said:

The x265 open source encoder is not mature enough to give you great quality all the time. With the same settings, it could produce a great encoding of a particular movie, yet produce a crap encoding on another movie, you still have to tweak some parameters from video to video if you want good quality rips.

Hardware hevc encoders (like the ones in video cards) are optimized to be very fast, but don't use all the features hevc has, so the quality is not the best. You'd have to increase the bitrate quite a bit to get the quality you already get with h264, so it makes no sense unless you really need hevc content.

 

Overall, if you had the original bluray and you'd make a rip, with the best settings in x265 you'd get a file that's around 70% the size of a rip encoded in h264. It's not worth spending 10-14 hours per encode just to save 500MB - 1 GB per video and your portable devices should already support h264 content quite well already.

 

And re-compression from already compressed h264 to HEVC will introduce additional losses, it's like compressing from MP3 to AAC ... each codec has its own way to save bits when shrinking something down to a size, so when compressing to hevc, you'll lose some more quality. It's not worth it. 

 

Also keep in mind that hevc decoding (even when done in hardware) will use more energy, so a phone or some laptop will play less minutes of hevc video compared to h264 videos.

 

I didn't realize that it wasn't mature since it's been out for like 3 years now. Also the reason i'm talking about re-encoding is because blu-rays are already encoded in H264. I thought HEVC (H265) was built on top of that so it could be compressed without loss but I now know that it was just a naming thing and they aren't built on top of each other.

 

Honestly the battery part isn't an issue, but I don't want to make the video double lossy.

19 hours ago, Vitalius said:

I've done a ton of testing on this. 

Blu-ray rips that are lossless can be around 12-20GB in size with x264. Converting to x265/HEVC at 1,500 Kb/s using Handbrake with 2-pass encoding, I can get those files to around 1.2-2GB without noticing a loss in quality. 

If the normal Handbrake won't work for you for some reason (I've noticed it breaking on some files), try a nightly build as that sometimes fixes it for me. 

YMMV. HEVC is best at long content. I go from 12 GB -> 1.2 GB regularly for movies, but for episodes that are regular length (say 23-27 minutes), I go from something like 350MB to around 330MB. Not worth the effort, but those aren't (effectively) lossless. (Effectively) lossless x264 (assume huge bit rate) for such an episode can put it at the 1.1-2GB range which after HEVCing at 1,500 Kb/s puts it at around 400-500 MB (since it has higher quality to begin with).

Note that the above CPU setting was Medium. HEVC doesn't support hardware acceleration via GPUs and such. 

Blu-rays themselves are lossy so a lossless rip of a blu-ray is already compressed. Re-encoding it with HEVC would be double lossy which is what I was trying to avoid but I see that's not possible. Also encoding time isn't really an issue since I can just let it run overnight.

[bobhays]

14 hours ago, Zodiark1593 said:

For my Cardcaptor Sakura Blu Ray series, I'm wondering if it would be worthwhile to perform a re-rip and encode with x265 for 1500 kbps. Currently at h.264 with the same bit trate. Only concern is none of my devices save for Nala (desktop) can play h.265 video in hardware, and my phone is confined to software only. 

 

10 hours ago, Zodiark1593 said:

I have the Blu Rays, I can rip them again is what I was mentioning. Not re-encoding the stuff already on the hard drive. 

 

I know enough about A/V to know multiple lossy encodes is a horrible idea. 

The problem is blu-rays are already h264. "re-rip and encode with x265" is actually re-encoding

 

EDIT: that was sort of the problem I was trying to solve with this thread but I guess it's not possible.

[Zodiark1593]

8 hours ago, bobhays said:

 

The problem is blu-rays are already h264. "re-rip and encode with x265" is actually re-encoding

 

EDIT: that was sort of the problem I was trying to solve with this thread but I guess it's not possible.

Blu Rays may also use VC-1.

 

Unless you have access to the raw source files, you're unlikely to bypass the encoding in the mastering for the Blu Rays. The goal in this case is to reduce file size while maintaining similar, or acceptable quality. 

[bobhays]

3 hours ago, Zodiark1593 said:

Blu Rays may also use VC-1.

 

Unless you have access to the raw source files, you're unlikely to bypass the encoding in the mastering for the Blu Rays. The goal in this case is to reduce file size while maintaining similar, or acceptable quality. 

I see, the difference was that I wanted to maintain the blu-ray quality while converting to HEVC which isn't possible, but you'd prefer to compress it regardless for the file size savings. The ironic thing is I usually encode a 2nd copy of the rip to make it more mobile friendly (less than 4gb). So i can take it on my phone or put it on a FAT32 flash drive, and now it seems like HEVC is the better option for my mobile copy even though it requires more processing. I'll probably just stick with h264 because of the compatibility and ease of use.

[Zodiark1593]

55 minutes ago, bobhays said:

I see, the difference was that I wanted to maintain the blu-ray quality while converting to HEVC which isn't possible, but you'd prefer to compress it regardless for the file size savings. The ironic thing is I usually encode a 2nd copy of the rip to make it more mobile friendly (less than 4gb). So i can take it on my phone or put it on a FAT32 flash drive, and now it seems like HEVC is the better option for my mobile copy even though it requires more processing. I'll probably just stick with h264 because of the compatibility and ease of use.

You could go with a high quality encode to play on your desktop, and then use a fast encode method from there when you want to put it on your mobile devices. On the smaller screen, minor quality hits are unlikely to be noticed. 

[bobhays]

1 hour ago, Zodiark1593 said:

You could go with a high quality encode to play on your desktop, and then use a fast encode method from there when you want to put it on your mobile devices. On the smaller screen, minor quality hits are unlikely to be noticed. 

But even a fast encode on a movie will take a good 30 minutes. I like to keep the copy so I can use it whenever I want, for example if i'm going to a friends place I just put the copy on a flashdrive or dvd and im good. I'm also working on my freeNAS setup so having the mobile version will allow me to stream it without transcoding

[BrightCandle]

It should be noted VP9 is pretty mature and produces similar quality at similar bit rates. At very constrained bit rates HEVC is superior and with a bit of time I imagine it will be better but there is a reason why youtube adopted VP9.