PCM vs bitstream with PS3

[notig]

I know this has probably been asked a bunch of times.. And I have read through the threads but I am still slightly confused about this. Can someone correct me?

For PCM which is uncompressed audio... there is no decoding involved therefore it won't make a difference whether you send it via bitstream or LPCM over HDMI from the PS3 to your receiver right?

For codecs which do have to be decoded such as TrueHD... you have to send it as LPCM and not bit stream because the ps3 does not support sending it over bit stream right?

Here is a point of further confusion.. if the ps3 can't send trueHD over bitstream but can send PCM over bit stream that must mean it is not an issue of bandwidth since the uncompressed audio would take up just as much or more space right? What is the issue with this?

I am planning to set up a home theater with a Denon 789 for christmas... if I set it up to decode on the PS3... in what possible situation would I actually want it to bit stream instead? I remember someone mentioning something about DD es or something which is 6 channel audio?

[Slec]

For Multichannel HD audio, the PS3 decodes internally and sends out as LPCM to receiver. If you bitstream you will get the lossy track.

edit:
HDMI
bitstream=lossy track
LPCM=hd audio decoded (based on info selected at setup) and sent to receiver.

Optical/Toslink
bitstream= lossy track
LPCM= 2.0 lossless track.

[notig]

Originally Posted by Slec

For Multichannel HD audio, the PS3 decodes internally and sends out as LPCM to receiver. If you bitstream you will get the lossy track.

edit:
HDMI
bitstream=lossy track
LPCM=hd audio decoded (based on info selected at setup) and sent to receiver.

Optical/Toslink
bitstream= lossy track
LPCM= 2.0 lossless track.

Don't some blue ray movies have pure pcm audio which doesn't have to be decoded though and can be bitstreamed over HDMI?

[ozzman]

https://forum.blu-ray.com/showthread.php?t=24132

[crackinhedz]

For codecs which do have to be decoded such as TrueHD... you have to send it as LPCM and not bit stream because the ps3 does not support sending it over bit stream right?

Here is a point of further confusion.. if the ps3 can't send trueHD over bitstream but can send PCM over bit stream that must mean it is not an issue of bandwidth since the uncompressed audio would take up just as much or more space right? What is the issue with this?

you can set it as Bitstream, but in reality its being sent as Linear PCM.

Kind of by default.

[crackinhedz]

Originally Posted by notig

I am planning to set up a home theater with a Denon 789 for christmas... if I set it up to decode on the PS3... in what possible situation would I actually want it to bit stream instead? I remember someone mentioning something about DD es or something which is 6 channel audio?

you may want to send Bitstream when watching a standard dvd. Which would allow Receiver access to Dolby EX and Dts ES audio tracks. For Blurays and internal decoding, it should be on Linear PCM.

[notig]

Originally Posted by ozzman

https://forum.blu-ray.com/showthread.php?t=24132

Like I said... I already read that thread.. there is to much misinformation to be of use to me.

I still do not understand the limitation of the PS3. If it is using a hardware or software decoder... well it doesn't matter if the limitation is not being able to send bitstream because then it isn't doing any decoding. Therefore if the limitation is bandwidth... isn't uncompressed audio after decoding the same size or even greater than the high definition formats such as trueHD... but yet it can get sent to the receiver.

[Slec]

Originally Posted by notig

Like I said... I already read that thread.. there is to much misinformation to be of use to me.

I still do not understand the limitation of the PS3. If it is using a hardware or software decoder... well it doesn't matter if the limitation is not being able to send bitstream because then it isn't doing any decoding. Therefore if the limitation is bandwidth... isn't uncompressed audio after decoding the same size or even greater than the high definition formats such as trueHD... but yet it can get sent to the receiver.

I think the first thing that needs clearing up is PCM and bitstream. They are two different ways of sending information.. therefore you cannot bitstream a PCM signal. PCM is the result after decoding (no matter where the decoding occurs). If you are listening to PCM off a disc, then it can only be sent out over HDMI as PCM.

bandwidth limitations come into play with toslink and PCM..

[notig]

Originally Posted by Slec

I think the first thing that needs clearing up is PCM and bitstream. They are two different ways of sending information.. therefore you cannot bitstream a PCM signal. PCM is the result after decoding (no matter where the decoding occurs). If you are listening to PCM off a disc, then it can only be sent out over HDMI as PCM.

bandwidth limitations come into play with toslink and PCM..

from what I gather... PCM is simply the bit representation of an analog signal... that is uncompressed. THe purpose of formats such as dolby TRUeHD.. is to offern an alternative that is compressed... but of the same quality.. So basically once you decode the TrueHD you get the PCM which is the uncompressed... bit representation of the audio.

Now here is the confusion.. If the ps3 can send PCM to the receiver after decoding whichever format it is in through LPCM.. well after it is decoded then it is at its biggest value.. it can't be smaller than before decoding it. therefore if the ps3 has a limitation of bitstreaming something it can't be because of bandwidth

[Slec]

Originally Posted by notig

from what I gather... PCM is simply the bit representation of an analog signal... that is uncompressed. THe purpose of formats such as dolby TRUeHD.. is to offern an alternative that is compressed... but of the same quality.. So basically once you decode the TrueHD you get the PCM which is the uncompressed... bit representation of the audio.

Now here is the confusion.. If the ps3 can send PCM to the receiver after decoding whichever format it is in through LPCM.. well after it is decoded then it is at its biggest value.. it can't be smaller than before decoding it. therefore if the ps3 has a limitation of bitstreaming something it can't be because of bandwidth

The PS3 lacks the hardware to bitstream the lossless information after being read off the disc (if memory serves, the first chip able to bitstream HD codecs came out after the PS3 launch and Sony has not upgraded the chip on any models since). It does however contain the hardware to pass on the LPCM signals after decoding.

[Big Daddy]

PCM is not the end of the story. The receiver or pre/pro still has to convert the PCM to analog and send the analog signals to the speakers. The quality of the sound that you hear is partially dependent on how well the receiver or pre/pro does its job of converting the digital signal to analog.