Blu-ray video and Audio questions

[AranhaHunter]

Okay, I've been here for awhile but I have a question on Blu Ray quality on both video and audio. I know the video can be encoded in some formats (MPEG 2, AVC, VC1, etc) and audio can be 5.1 Dolby Digital, PCM, Dolby TrueHD, and DTS-HD Master Audio etc...

Can someone please rank ALL available Audio and Video encodes from best to worse? Also is a higher bit rate better or worse? Is ia higher aspect ratio better or worse?

[SS316SRV]

Aspect Ratio has nothing to do with quality.

High Bitrates are better.

PCM, TrueHD, Master Audio all sound the same.

AVC is found on the best transfers.

[theprophecy247]

Originally Posted by SS316SRV

Aspect Ratio has nothing to do with quality.

High Bitrates are better.

PCM, TrueHD, Master Audio all sound the same.

AVC is found on the best transfers.

good stuff here +1

[Carlsberg19]

I havent a clue between all the different audio formats out there, how do i know if my reciever gives HD sound as opposed to DTS, ohh i dunno lol

[aramis109]

There is no one "bad" video or audio codec. It's all dependant on what's put in there to begin with. Garbage in = garbage out, regardless of codec. That said, Disney is doing a hell of a job with AVC consistently. There are some very good MPEG-2 flicks but they are few and far between. Most studios have gone away from them entirely at this point.

Audio is completely dependent on the master, same as video. However, DTS-HD MA, TRUEHD, and PCM are the lossless audio formats that will produce the best sound. Core DTS, DD, etc are lossy and don't have the bandwidth to compete.

As for the last question on your AVR, I would recommend to check the manual. First off, does it have HDMI? Does it do passthrough? Can it accept 5.1/7.1 analog connections?

These are questions that'll tell you if it has lossless or not. Since you have to ask though, I'm going to go out on a limb and say no, it doesn't.

[Anthony P]

DD and DTS are lossy, that means that in the end you won't get back (out from your speakers) what was originally there on the digital master.

DTHD and DTS-HD MA are lossless that means that if everything is done right you should get back the same as the original digital master

PCM is the original digitally sampled audio it is what is used before compression and what the compressed audio gets decompressed into before the DACs bring it from digital (bits) to analog (sound)

To complicate matters sound is analog, that means that you must digitally sample it. How it works is that every few fractions of a second a sample of the audio wave is taken this is measured in khz, and at each sampling point it records the “height”, the height is then given a value how many different heights there can be is determined by the bit depth. That is why you will see stuff like 48/16 or 96/24. 48/16 means 48k images are taken every second and there can be 16 bits of values for each image (i.e. 65k) while the other is a much better representation with 96k samples with a precision of 24 bits (or 16M). So if you have two digital masters the one at 96/24 would be better quality (more precise) then the one at 48/16.


As for video, it is much more tricky. You will never get the original and you will never get lossless. Each CODEC has it’s own pros and cons and so there is no “this CODEC is better” in reality for the same CODEC the higher the bitrate the better (less information is destroyed). This makes it even harder to talk about what CODEC is better because even if one was to assume A is better then B, all one would need to do is make an unjust example where A is bitstarved and B has enough to get back a better image.

[Anthony P]

I forgot aspect ration, this is a tricky one.
SS316SRV is right in a way (it does not have to do with PQ) but the AR describes a picture. If it is 16:9 (or 1.78:1) then it takes up the full screen of your image, any other AR would mean that there would be black bars if it is 4:3 (1.33) then there would be black bars on the side and if it is larger then 1.78 then black bars above and below. The reality is that black bars (since there is nothing but a uniform black picture in them) should be easier to encode (there is no detail to be lost compressing in that area) so in essence if a movie is not 16:9 it should be easier to compress, so if I took content that was 16:9 and compressed it and then I covered part of it with black bars (to make it shorter or less wide) and compressed it at the exact same bitrate that second movie would look a bit better.

On the other hand demand for OAR has nothing to do with PQ. The reason people like wider films is that most where originally shot wider for the cinema. If a film was shot in 2.35 then showing it in 1.78 means that some of the scene on the sides where cut.

The opposite side of this is that if a film that was 2.35 is letter boxed to be 1.78 then it is smaller and covered by less pixels then by pan and scan. Most people would rather sacrifice some fine detail to have the full picture ( think about it, is it better to have the full detail of some lines on a shirt or seeing the person that they are talking to who would be off camera if the scene was cut to fit)

note these would equally apply if the OAR was 4:3 (made for TV) except the cutting would be up and down instead of side ways

[Petra_Kalbrain]

Originally Posted by SS316SRV

Aspect Ratio has nothing to do with quality.

High Bitrates are better.

PCM, TrueHD, Master Audio all sound the same.

AVC is found on the best transfers.

I agree with everything except the AVC comment...

Statistically, there are far many more "better quality" AVC encodes than there are VC-1 encodes. However, that isn't to say that VC-1 can't be just as good. If you look at New Line titles that are encoded in VC-1 they are just as good as ANY AVC encode on the market. The only reason people say AVC is better is because of what Warner has been doing with their "dual format" encoding since the dawn of the format war. With the proper bitrate, VC-1 and AVC are absolutely and unequivocally able to produce the same quality.

P.S. Many people find DTS HD MA audio to be the best with PCM close behind and TrueHD sounding flat... and that includes me. But, many will argue with, "Shut up Petra, you don't know what you are talking about. They are all identical." Not to my ears though.......... not... to... my... ears...