I was playing bluray disc last night night and i noticed i had the options of having the audio in either Dolby Digital 48Khz or PCM 48Khz/16 bit. Which would give the best sound quality? I have the dvd player audio connected via multi channel out to the amp. any advice please?
Dolby Digital or PCM audio?
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PCM without a doubt. Although you should listen for yourself to see if you notice a difference - this will depend somewhat on your set-up and speakers.
Pulse Code Modulation. It's basically the form of sound that digital sound is decoded into to be outputted to the speakers. In the case of Blu-Ray, it is high-bit rate uncompressed audio that should be significantly better than the standard compressed Dolby Digital track.
i thought dolby digital was the best, because used in cinemas etc? and yes, im new to this before you ask
professorhat
Well-known member
Nope, PCM is uncompressed, Dolby Digital is highly compressed. It's like the difference between a CD imported as a WAV file and a 128 Kbps MP3 in computer audio terms - the WAV file will be much better quality than the MP3 as no lossy compression has occurred.
I did watch Batman Begins in PCM, then I Bitstreamed DD Dolby True Hd sound, It did sound a duller then the PCM. So whats the point of DD True HD then. Experts and reveiws say in Dolby True Hd you are listing to the sound track the same as the master recording and as the director intended. Somebody please explain
professorhat
Well-known member
Interesting, my copy of Batman Begins doesn't have a PCM soundtrack. Anyway, the difference is, Dolby TrueHD (and DTS HD Master Audio) are lossless compression formats (like Apple Lossless or FLAC in the computer audio mode). This means they are compressed, but without any loss to the original detail in the soundtrack. As a result they take up less space on the Blu-Ray disc which might be required if there are lots of extras etc. Which format is used is entirely up to the studio that produces the disc.
i agree, if PCM is better quality, why would it be the second option the the gisc and not the default option, is this normal?
professor, could you post a reply of the audio options from best to worst quality? im still confused...
markthelifeguard:i agree, if PCM is better quality, why
would it be the second option the the gisc and not the default option,
is this normal?
Because the BD specification mandates that players must support Dolby Digital, DTS and Linear PCM.
Discs must have one of these formats, though there's actually no requirement for them to have the high-resolution variants of Dolby Digital or DTS, so Dolby is usually chosen as the default soundtrack as it's the simplest one for the player to downconvert between the HD and the standard version.
And of course Dolby Digital is the most back-compatible surround format when it comes to legacy surround amps and receivers.
In short, it's a compatibility thing.
would it be the second option the the gisc and not the default option,
is this normal?
Because the BD specification mandates that players must support Dolby Digital, DTS and Linear PCM.
Discs must have one of these formats, though there's actually no requirement for them to have the high-resolution variants of Dolby Digital or DTS, so Dolby is usually chosen as the default soundtrack as it's the simplest one for the player to downconvert between the HD and the standard version.
And of course Dolby Digital is the most back-compatible surround format when it comes to legacy surround amps and receivers.
In short, it's a compatibility thing.
professorhat
Well-known member
markthelifeguard:professor, could you post a reply of the audio options from best to worst quality? im still confused...
Well, in theory PCM, Dolby TrueHD and DTS HD Master Audio should be the same as the last two are just lossless compressions of the PCM soundtrack meaning once they are decoded (either onboard by the player or by a suitable AV amplifier), there shouldn't be any difference. However, many people maintain that a PCM soundtrack is better since it doesn't have to go through the decoding process - my own listening agrees with this.
After that, there are a couple of other lossy formats called Dolby Digital Plus and DTS HD High Resolution Audio. These are lossy compression formats so are not as good as the above three, but still contain more detail than the old Dolby Digital and DTS soundtracks. You will rarely see these used on a Blu-Ray.
Finally, there is regular Dolby Digital and DTS. These are the same formats as used on DVDs (although the bitrate is slightly higher on Blu-Ray, so they are still a bit better than the DVD equivalent).
You can read all about Dolby and DTS and the different formats at the links provided.
Well, in theory PCM, Dolby TrueHD and DTS HD Master Audio should be the same as the last two are just lossless compressions of the PCM soundtrack meaning once they are decoded (either onboard by the player or by a suitable AV amplifier), there shouldn't be any difference. However, many people maintain that a PCM soundtrack is better since it doesn't have to go through the decoding process - my own listening agrees with this.
After that, there are a couple of other lossy formats called Dolby Digital Plus and DTS HD High Resolution Audio. These are lossy compression formats so are not as good as the above three, but still contain more detail than the old Dolby Digital and DTS soundtracks. You will rarely see these used on a Blu-Ray.
Finally, there is regular Dolby Digital and DTS. These are the same formats as used on DVDs (although the bitrate is slightly higher on Blu-Ray, so they are still a bit better than the DVD equivalent).
You can read all about Dolby and DTS and the different formats at the links provided.
'The original poster has his bluray via 'multichannel' to his amp, so this sounds like analogue multichannel - which may well even further removed from comparing PCM with Dolby/DTS bistreams.
Multichannel analogue requires the bluray player to read the 'digital' soundtrack and internally decode (if necessary i.e. not yet pcm channels) and then convert the pcm channels to the separated analogue 5.1 signals which are then fed out to a waiting amplifer which just amplifies.
I am not sure whether users can choose which digital format on the bluray for the player to use as its source to create the 5.1 multichannel out, whereas users do have the choice which format is sent via HDMI as a digital signal.
Anyone know?
Multichannel analogue requires the bluray player to read the 'digital' soundtrack and internally decode (if necessary i.e. not yet pcm channels) and then convert the pcm channels to the separated analogue 5.1 signals which are then fed out to a waiting amplifer which just amplifies.
I am not sure whether users can choose which digital format on the bluray for the player to use as its source to create the 5.1 multichannel out, whereas users do have the choice which format is sent via HDMI as a digital signal.
Anyone know?
I have a Sony BDP-S550 Blu-Ray player with audio via the multi-channel outputs. This player supports a whole host of analogue signals from 2 channel PCM up to 8 channel DTS-HD Master Audio. However you are limited to what source is available on the disc. Can't say for others manufacturers players.
Have not heard PCM 5.1 yet, but I do prefer DTS over Dolby Digital. Greater dynamics, detail, volume. If I remember correctly DTS uses a higer bit rate than DD??
Have not heard PCM 5.1 yet, but I do prefer DTS over Dolby Digital. Greater dynamics, detail, volume. If I remember correctly DTS uses a higer bit rate than DD??
professorhat
Well-known member
shreddy:I am not sure whether users can choose which digital format on the bluray for the player to use as its source to create the 5.1 multichannel out, whereas users do have the choice which format is sent via HDMI as a digital signal.
Using multichannel outs, all that's happening is the soundtrack is being decoded onboard by the Blu-Ray player, rather than being decoded by the amplifier. So long as that player can decode all the formats onboard therefore, you can choose any of the soundtracks on offer.ÿ
Using multichannel outs, all that's happening is the soundtrack is being decoded onboard by the Blu-Ray player, rather than being decoded by the amplifier. So long as that player can decode all the formats onboard therefore, you can choose any of the soundtracks on offer.ÿ
i suppose a slight disadvantage of using PCM rather than Dolby Digital would be the loss of the Subwoofer or does that not really play much of an effect.
professorhat
Well-known member
My Onkyo AV receiver can pass thru a signal or change it to a preferred sound format. My Dish Hopper seems to output PCM mostly. Should I chose a pass thru or just chose the mode that sounds best. If PCM is the best, why chose another mode?
Anonymous said:
PCM doesn't mean a specific number of audio channels. I've got a couple of films with PCM 7.1 one of them is Ultimate Avengers and Ultimate Avengers 2
As an Audio codec PCM works the same way as any of the Dolby Digital, DTS, SDDS and other multichannel audio. The only difference is nothing is manipulated. The DTS, DD and so on ones are adjusted to meet the spacifications they set for their product.
This is an old thread but just in case someone else comes along to read I'll give my 2 cents worth. As long as you have a system that is capable of working with compressed dolby digital, and most people should, then using that is fine. I've read comments here about compression being lower quality than uncompressed, and theoritically that's true. However, to what your ears can percieve, it's not true. As long as there is enough bandwidth for the sound, compressed audio sounds the same to the typical listener. With music that bandwidth happens to be around 192kbs. Music has much more depth than does a typical movie, so even lower rates can be used for most movie sound.
A test was done via Maximim PC over music compression compared to uncompressed sound and this is what they found:
Using a collection of people that had different tastes of music, they played the person music they were familiar with and unfamilier with, including different genres (classical, jazz, rock, etc...) . They had to guess which was which. The compression used 128kbs, 192Kbs, 256Kbs and 320Kbs. They found that people guessed wrong as much as they did right, EVEN with music they were familiar with. This suggests that people couldn't tell the difference. Now, viewing the waves of the sound showed differences with the lower compression rates, but once the rate was up to 256Kbs, the differences were incredibly small. Typically the compression rate of an audio track on a bluray is pretty high, meaning there is plenty of bandwidth, so the compressed audio doesn't suffer from the inablity to keep track of the entire sound range, and start generating sound artifacts, just as what happens with the compressed video you are looking at while you are watching the movie. The video is compressed. As long as the cameras are high quality, I see fantastic images from bluray. The same is true with sound. As long as the sound was recorded well, using good equipment, then the compressed version of that sound is perfectly fine. People who say otherwise have probably never done a side by side test with a good collection of sound files to know what they are talking about.
A test was done via Maximim PC over music compression compared to uncompressed sound and this is what they found:
Using a collection of people that had different tastes of music, they played the person music they were familiar with and unfamilier with, including different genres (classical, jazz, rock, etc...) . They had to guess which was which. The compression used 128kbs, 192Kbs, 256Kbs and 320Kbs. They found that people guessed wrong as much as they did right, EVEN with music they were familiar with. This suggests that people couldn't tell the difference. Now, viewing the waves of the sound showed differences with the lower compression rates, but once the rate was up to 256Kbs, the differences were incredibly small. Typically the compression rate of an audio track on a bluray is pretty high, meaning there is plenty of bandwidth, so the compressed audio doesn't suffer from the inablity to keep track of the entire sound range, and start generating sound artifacts, just as what happens with the compressed video you are looking at while you are watching the movie. The video is compressed. As long as the cameras are high quality, I see fantastic images from bluray. The same is true with sound. As long as the sound was recorded well, using good equipment, then the compressed version of that sound is perfectly fine. People who say otherwise have probably never done a side by side test with a good collection of sound files to know what they are talking about.
Sliced Bread
Well-known member
If that's the case then dolby digital will sound no different to dolby true hd.
i think it's pretty much accepted by anyone whos heard the two formats that the later is superior.
likewise, I've had several DVDs woth dolby digital and pcm or Dolby digital and dts and on most occasions the higher bitrate is an improvement.
i think it's pretty much accepted by anyone whos heard the two formats that the later is superior.
likewise, I've had several DVDs woth dolby digital and pcm or Dolby digital and dts and on most occasions the higher bitrate is an improvement.
Hi I'm using creative audigy fx sound card on windows 8.1(5.1 philips hometheatre). I'm big fan of 5.1 surround sound.My doubt is that KMplayer has pcm output, SPDIF output and Lpcm output options in internal audio decoder(output) settings.If i have to get surround sound which output i can select? I do not know what is SPDIF. Not more than that which one can select LAV audio codec and kmp audio codec in internal audio decoder.Also I've confused to select options in "decoder usage" options given below > internal video decoder,external video decoder,internal audio decoder and external audio decoder. Please give the details to get a 5.1 sound and settings of "decoder usage" according to have mentioned above. I hope that u will solve my problem.
Guys its true that PCM sound a bit raw and loud, but its a bit too much sound for me, DD sound a bit more refined. PCM is like a laser beam sharp and to a point.. DD is like a warm room light sweet clear and spaced out.. DD is less hash on the ear drums.....if you’re home and hang over PCM is not something you would tolerate. Instant headache....Hope i simplified it for you..
Something not quite right with your set up if PCM is harsh. If anything it should sound less crisp and much closer to real life than DD does. DD is processed that's why it sounds more refined (fake) where as PCM is straight from the desk basically.
If it's too loud turn it down.
If it's too loud turn it down.
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