Discussion Forums > Technology
Question about encoding
GadgetAddict:
Hi All,
Hope this isn't posted in the wrong place. I have been downloading a lot of BD rips of various animes, and have been noticing something. These videos are being encoded with a very high number of reference frames. Obviously a higher number of reference frames can be good for image quality, but it presents a few problems. 1. It puts a higher strain on playback devices and 2. It prevents the conversion of these (typically) MKVs to physical media without completely re-encoding the video.
For example, I downloaded a 16GB torrent of High School of the Dead, bluray rip. It had 16 reference frames encoded. The max for 1080p is 4. h264 is a lossy format, so re-encoding, even at the same bitrate is going to degrade quality, not to mention, re-encoding takes me pretty much a whole day at 2-pass very high quality settings on my i7 @ 4.0 ghz...
Does anyone on this forum do encoding? If so, why with the reference frames? Also, noticed the large amount of files utilizing FLAC format, which is uncommon in other ripping/encoding groups...
Finally, this isn't a complaint, so please don't attack me with the "shut up and take it how it is". Just wondering.
Lupin:
--- Quote from: GadgetAddict on July 26, 2011, 11:45:56 PM ---Hi All,
Hope this isn't posted in the wrong place. I have been downloading a lot of BD rips of various animes, and have been noticing something. These videos are being encoded with a very high number of reference frames. Obviously a higher number of reference frames can be good for image quality, but it presents a few problems. 1. It puts a higher strain on playback devices and 2. It prevents the conversion of these (typically) MKVs to physical media without completely re-encoding the video.
For example, I downloaded a 16GB torrent of High School of the Dead, bluray rip. It had 16 reference frames encoded. The max for 1080p is 4. h264 is a lossy format, so re-encoding, even at the same bitrate is going to degrade quality, not to mention, re-encoding takes me pretty much a whole day at 2-pass very high quality settings on my i7 @ 4.0 ghz...
Does anyone on this forum do encoding? If so, why with the reference frames? Also, noticed the large amount of files utilizing FLAC format, which is uncommon in other ripping/encoding groups...
Finally, this isn't a complaint, so please don't attack me with the "shut up and take it how it is". Just wondering.
--- End quote ---
Most anime encoders don't give a damn about hardware playback.
Non-anime ripping/encoding groups (particularly the Scene) have strict rules (quite ancient rules IMO) that requires hardware compatibility.
kureshii:
The max ref frames supported in the h264 spec is 16. But most hardware playback devices only support up to Level 4.x, which allows 4 ref frames for 1080p and 9 for 720p.
A higher number of ref frames does not increase image quality, but may aid compression. You’ll have to appeal to the fansubbing/encoding groups to get them to lower ref frames if you want something done about that.
The FLAC audio tracks are typically encoded from lossless audio sources (DTS-HD MA or PCM). Those looking for a release they can watch straight away would likely balk at the filesize, but if you transcode your own MKVs for viewing (some do that for AC3 compatibility with their AV receivers, for instance), FLAC audio is a pretty nice thing to have. Again, rage at the fansub group if you want that changed.
I’m fine with both practices, although I can see why they cause some leechers no end of grief.
GadgetAddict:
I rip/backup my own blu-rays pretty frequently and I do know from my own experience that animated/non-live action material handles compression very very well. I definitely think that if they changed their ways from encoding with 16 reference frames to the typical 4 for 1080p, there would be no real drawbacks that would be discernible. What is the best way to contact these fansubbers/encoders? I'd like to maybe chat with them if at all possible :)
kureshii:
Most groups have IRC channels, listed on their fansub page, which is usually a google search away.
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