It would appear I'm answering my own questions.....hummm
I found this on audio forum.
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The title says it all..
What exactly is the difference between Bitstream vs. Linear PCM? ... the two options you have to choose from when choosing HDMI Audio Out from the settings. What exactly do I need to choose in order for the sound to come out the way it should? Does Linear PCM need to be chosen in order for PCM soundtracks from a blu-ray disc to output at its optimum?
When I play Pursuit of Happyness in 5.1 PCM (Bitstream enabled), my receiver will show that PCM is active. When I play it in 5.1 English (Bitstream enabled), my receiver will whos that Dolby Digital is active. But the 5.1 English sounds louder than the 5.1 PCM. But shouldn't that be the other way around... 5.1 PCM is uncompressed. When I play both soundtracks with Linear PCM enabled, my receiver will only show PCM active (even if I play the 5.1 English soundtrack).
Any help is appreciated.
Thanks
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Bitstream is basically the raw undecoded data being sent to the receiver for it to decode. PCM means that the PS3 is converting to PCM and sending it to the receiver which pretty much all receivers understand.
HDMI has the bandwidth for 8 channels of uncompressed pcm audio while optical only has capability for 2 channels of uncompressed audio.
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You can think of the DD track like a .zip file on your computer and the PCM like a .wav file on your PC. The receiver can only play .wav sound (PCM) so at some point it needs to unzip (or decode) the DD track into a PCM stream in order to play it. Setting the PS3 to bitstream makes the PS3 send whatever's on the disc to the receiver, where setting to Linear PCM causes it to be converted to PCM in the player before sending to the receiver. Hence, when playing the PCM soundtrack, the receiver gets PCM regardless of the setting.
You might want to leave the setting as Bitstream so at least you know when you're accidently using the DD soundtrack because your receiver will tell you. In terms of volume, this is seperate from compression. Compression will cause the sound quality/clarity to decrease but it can still be recorded at a much higher volume to give you poor quality but very loud sound in comparison to the PCM soundtrack.
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Assuming we have an receiver capable of accepting PCM audio via HDMI, which is the 'better' way?
Should we have the PS3 decode or have the receiver decode?
Would there be a difference?
I have a PS3 and a Sony DG810. I will try to do some testing tonight or tomorrow to see what my results are and if I can tell a difference or if I have any difficulties.
I just set it to use PCM because I wanted to have access to the PCM tracks when available. Learning new stuff everyday.
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You'll get the multichannel PCM tracks over HDMI even when HDMI is set to bitstream on the PS3. However, you lose sounds mixed and overlayed by the PS3 (e.g., menu sounds seen in numerous BD titles currently available) when listening to DD or DTS on BDs.
With regards to legacy DD and DTS, there is no quality difference between the PCM and bitstream settings with my Denon AVR-4306. For me, setting the PS3 to decode DD or DTS results in the same quality as when letting my receiver directly handle the lossy codecs. I tested this by using numerous movie scenes that strongly engage all channels.
I have my PS3 set to PCM, because this way my Denon applies its AL24 processing regardless of what I'm listening to, and I always get sounds mixed by the PS3 itself.
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I just want to clarify.. you probably already know this but just wanted to make sure you knew. The PCM tracks are available to play when I set the PS3 to bitstream... my receiver confirms it by showing "MPCM" when playing the 5.1 PCM track as opposed to "Dolby Digital" when playing the 5.1 Dolby track.
Please let us know what you're able to learn when testing.
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Quote:
Originally Posted by ase8776 View Post
The title says it all..
What exactly is the difference between Bitstream vs. Linear PCM? ... the two options you have to choose from when choosing HDMI Audio Out from the settings. What exactly do I need to choose in order for the sound to come out the way it should? Does Linear PCM need to be chosen in order for PCM soundtracks from a blu-ray disc to output at its optimum?
Linear PCM is recommended over regular DD.
Quote:
When I play Pursuit of Happyness in 5.1 PCM (Bitstream enabled), my receiver will show that PCM is active. When I play it in 5.1 English (Bitstream enabled), my receiver will whos that Dolby Digital is active. But the 5.1 English sounds louder than the 5.1 PCM. But shouldn't that be the other way around... 5.1 PCM is uncompressed. When I play both soundtracks with Linear PCM enabled, my receiver will only show PCM active (even if I play the 5.1 English soundtrack).
Did you switch from HDMI to Optical output when you noticed this difference?
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Using only optical, it isn't possible to get the best performance.
You have to choose between multichannel (5.1, 7.1) compressed sound (ie like MP3s) or lossless 2 channel sound (akin to CD or even as good as SACD or DVD-A with some movies).
You can fake multichannel using something like Dolby Prologic and still retain the benefits of lossless which some people like. You should try both methods and see which you like the better.
Nothing beats getting both lossless and discrete multichannel output. HDMI is the only way to achieve this. But if you can't hear the difference between lossless and lossy compression then all the better for you and your wallet.
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linear pcm if you want uncompressed audio. bitstream if you want regular Dolby digital.
seriously, if you want uncompressed audio, go with pcm. not everything has this, but its worth it if it does. just played some folklore in uncompressed, and man, it has some good sound.
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since no one has answered the question which is better bit stream or PCM, i will answer it for anyone that wants to know. pcm is better , it is loss less audio and it's the way the original is supposed to sound. typically DD double digital which is sent bit stream is around 600 kb and pcm loss less is usually sent around 5.0+ mbs . the pcm track will be much clearer and more i guess defined when compared to double digital, but you must have a receiver that excepts pcm audio like my onkyo tx-sr604. you can clearly hear a difference between DD vs PCM and pcm is better. hope this helps
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The question is really about audio output modes on the PS3, not the audio formats on the disc. The audio track on the disc is either Linear PCM or a compressed format (which can be lossy, like DD/DTS, or lossless, like DD TrueHD or DTS-MA).
If you set the PS3 to output bitstream, then it will send exactly what's on the disc without modifying it at all, and it's up to your receiver to decode whatever needs decoding. If the PS3 is set to output PCM, then it will decode compressed formats into Linear PCM and send that LPCM stream to the receiver.
When you've selected a PCM soundtrack from the disc, then the PS3 will be sending PCM to the receiver regardless of the setting. However, as mentioned above, if the PS3 is set to bitstream then it won't be able to make any changes to the audio stream, such as mixing in menu sounds.
At this point, there's really no reason to select bitstream output on the PS3 unless your receiver has problems receiving multichannel PCM via HDMI. The PS3 is perfectly capable of decoding any of the available audio formats except DTS-MA (which is currently neither decoded nor passed as bitstream), and you get the ability for it to mix in additional audio.
The BD format is really designed for the player to do audio decoding anyway; the ability to pass the HD audio formats (DD TrueHD and DTS-MA) as bitstream to the receiver, which requires HDMI 1.3, is something that was demanded by the receiver manufacturers so that they could badge their receivers as "True-HD Capable" and "DTS-MA Capable". In reality, any receiver that can receive multichannel PCM over HDMI is capable of playing these formats, as long as the player does the decoding, which is what they're designed to do.
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Fresh mud anyone?
