As a precursor to my upcoming post on crafting my own hybrid encodes of this hidden gem of a show, I thought I'd compare the two sets of source material I'll be working with. Hopefully this will be useful all on its own for anyone thinking about acquiring either of them.
Note: All comparative screenshots, video clips, and audio files are encoded losslessly. The images and video are encoded at 8-bits per channel—dithered where appropriate—and after they have been IVTCed. Animated clips require Chrome for WebP support. For all comparisons, simply mouseover (or tap on mobile) the image to see the corresponding R2 DVD screenshot.
The two sets of matterial in question are: the R2 DVDs released in Japan in 2005, which can still be purchased new from Amazon.jp, and the R1 DVDs released by Bandai in North America in 2008. These unfortunately are no longer in print, but you can still find used copies online. In my encodes, the Japanese DVDs will be used for their higher-quality video track, and the R1 DVDs will be used for their English subtitles and dub track.
Compression & Encoding:
As you can see, MPEG-2 compression on the R2 DVDs is quite good, with good noise retention (above) and very few "destroyed" frames (below) around scene changes. This is much better than the over-compressed video on the R1 DVDs, and the primary reason I went out of my way to acquire both sets of discs.
There's really nothing you can do with frames this bad except delete them entirely, and you can only get away with so much of that. My preliminary scene-filtering script for episode one of the R1 DVDs had over 120 FreezeFrame() calls! Of course, this technique will not work on high-motion scenes, with long strings of unique frames. Fortunately, the R2 encodes also handle these quite well, as you can see in the following example:
I suspect that this is not only because the R2 encodes have a much higher average bitrate—8909kbps to the R1 DVD's 5997kbps—but a better distribution of those bits. Below is a bitrate distribution analysis from the first .mts stream in each DVD set. It is clear that the R2 DVDs have more variance, jumping to over 10000kbps at several points, although they are far from achieving the level of variation we take for granted today with modern video encoders.
R1 Bitrate Graph
R2 Bitrate Graph
One area where this doesn't appear to help, however, is during fades to or from solid black—a classic encoder trap. This is one of the big pitfalls with MPEG-2 itself, and not the fault of any one bad encoder. Fortunately, I had been working on a solution to this problem for the R1 DVDs before acquiring the R2 discs, and so I have already developed a set of AvsPmod macros (below) to re-create static fades.
I have GetFrame.py hotkeyed to shift+up, and FadeToBlack/FadeFromBlack assigned to shift+K/shift+J respectively. This lets me quickly assign the start of a range of frames while scrubbing back and forth with the arrow keys, then apply either function when I reach the desired end frame. I'll cover this in more detail in the follow-up post.
"Source artifacts" refers to visual problems present in the source material prior to compression. For all intents and purposes, there are no differences between either of these DVD sets in terms of these visual anomalies. Fortunately, the source material suffers from very little artifacting. As with most DVDs, the extremely low resolution and sharpness make aliasing almost a non-issue (after you correct for interlacing artifacts), and ringing and haloing are virtually nonexistent. Banding is similarly scarce, even more so due to the added noise transparency in the R2 DVDs. Below is an example from the R2 DVDs of some mild banding in Helga's hair, and some trace aliasing on her hands:
As you can see, these problems are hardly noticeable without close inspection. I am especially impressed with the low levels of banding and haloing, both of which are extremely common in anime DVDs.
Audio & Miscellaneous:
The audio quality on the Japanese DVDs is also far superior to that of their R1 counterparts. Both sets use AC3 encoding, but the R2 DVDs use a bitrate of 448kbps, compared with the R1 discs' measly 192kbps. The reduced bitrate is no doubt due to the need to squeeze in the additional dub track, but AC3 isn't exactly the most efficient codec on the planet, and bitstraving it this much is never a good idea. Since it's hard to objectively compare audio, I've included an sound clip from each copy of the Japanese-language track for you to listen to yourself:
R1 Audio Sample
R2 Audio Sample
Although it may be the only good thing about them, the R1 DVDs feature an excellent translation by Bandai. I won't bother giving examples, as it is the only decent translation available. Still, they deserve credit for this, if nothing else.
Finally, the R1 DVDs have no noticeable color color shift (or sabotage) when held up against the R2 discs, as you can see in the comparison below:
Colors are Identical in Both Releases
I hope this comparison was useful, or at least interesting, and if it was, that you'll check back again for the follow-up piece. I should have that done by the end of the month (no promises, though).
Next in Series:
Fantastic Children Restoration and Vapoursynth (Coming Soon!)