NTSC/PAL Blu-Ray Quality/Colour Comparison.

[Speeny]

I have ripped both my American copy of this Blu-Ray, and the Australian copy.
I wanted to do a comparison test with the two to see if there were any minor differences..to my surprise there is.
You can notice in the two images I'll upload down below, that the NTSC colour is much more smooth.
With the PAL colour on the other hand, you can slightly notice gradients in the colours. (Mostly in darker scenes.)

I am just wondering why this is, and is there a possible fix for the gradient issue with the PAL format? I used MakeMKV to rip both copies onto my computer.

Thanks!


NTSC


PAL

[Speeny]

Just to add, you can see the colour gradient on his shirt mainly, (on the PAL screenshot.)

[poisondeathray]

There can be several reasons for this.

Look on the box, was it the same studio that made them ?

Obviously different settings used for the encoder, and you might be comparing different frame types (I vs. B vs. P) - because the encoder GOP frametype distribution might be different. Look at the size of the PNG - they should be close to the same size, but it's 2.14 vs 1.54 MiB. 39% more. That is a very significant difference. Look at the quality difference , artifacts around the lines. This is likely a lower bitrate / higher quantizer encode and/or a b-frame vs. other frame type comparison. So have a look at other frames, but I'm going to assume this is representative. Look at the average bitrate and distribution of bitrate of each version (e.g. are some scenes "worse" than others?). You can use tools like mediainfo, bitrate viewer

To "treat" these types of defects you usually add dithering filters and re-encode at a higher bitrate (higher bitrates are required to retain the dither) . But I'd be tempted use the "NTSC" version and speed it up if you need a 25p version

Additionally "PAL" area blu-ray discs with 25p content are encoded interlaced, because 25pN (native) isn't allowed in the BD standard. Encoding interlaced is less efficient, will yield lower quality at the same bitrate. So even if the same studio, same encoder, same master, otherwise same settings etc... were used, the "PAL" version would be at a disadvantage

[Speeny]

@poisondeathray

Thanks for your reply.
Yes, some scenes are worse than others, the quality is consistent, but in the darker scenes, you can see that gradient type of effect or sometimes blurs. Here is another example. Also, the studio who released this in the states was Sentai Filmworks..here in Australia, a studio called Hanabee. I'm pretty sure their masters aren't any different, seeing as I just think they receive the American transfer.
You can tell from the NTSC (American copy) of the Blu-Ray rip, that this scene in particular is clear, and sharp.
The PAL version on the other hand is somewhat blurry.
It's not too noticeable, but there is a great difference when you look at the head especially.

NTSC




PAL

[poisondeathray]

Again, look at the size difference in the PNG. That is going to be proportional to the bitrate difference between the two, at least in the frames you presented. There are many factors, but bitrate is the most important for quality. It's analgous to "horsepower" for cars. If everything else is the same , the car with more horse power is going be better . You can check with mediainfo for example, or bitrate viewer

Yes, the "PAL" version not only has problem with gradient banding, but low quality. As you mentioned - look at how poor the lines in the "hair" are. This is common on many retail releases that aren't encoded properly , low bitrates, and not prepared properly with dithering. The quality control for that studio is probably low, and/or the compressionist had a bad day, or doesn't know what he is doing. Consistently lower quality in dark scenes suggests poor quantization and bitrate distribution. In the past it was common with studios that use CineVision, but very few studios use that now.

While gradient banding is fairly easy to "fix" (there are various techniques but the basic one is filtering and dithering. On a consumer level, typically avisynth is used) , those defects like the hair will be impossible to getting it look as crisp as the "NTSC" version. Too much is already lost from the poor compression job

[Brad]

It also looks like your decoder might be using point sampling for chroma (all shots).