It depends upon where the PCM digital data is derrived from and how it was encoded. It can technically be better by way of it allowing for higher bitrates, but setting a source device to output PCM rather than allowing it to bitstream the formats the content is encoded with simply results in the source converting other formats to PCM data. The audio you get resulting PCM data in such instances will be no better than the audio you'd have gotten had you bitstreamed the encoded audio the PCM data was derrived from.
In some instances, setting a device to output PCM as opposed to having bitstream the actual format the audio was encoded with can result in you getting audio that is less desirable. Choosing the PCM digital output option onboard a TV for example will in most instances result in 5.1 Dolby and DTS encoded formats being mixed down to just 2 channel PCM. Again, the resulting PCM would simply be the DTS or Dolby Digital audio decoded by the TV and mixed downso no improvwement over what you'd have gotten had you bitstreamed the original format.
The only time that PCM may resilt in better quality is in instances where you get the option of either a discrete PCM soundtrack or a Dolby encoded soundtrack. Even then, the PCM option will have to be encoded in a manner than actually means that the lossless uncompressed PCM data includes as much if not more data than the lossy compressed Dolby Digital audio.
Also note that your AV receiver decodes incoming formatted audio and this results in PCM data. It is this PCM data that is processed by the AV receiver and converted to an analogue signal by its DAC.
Streaming audio already encoded as Dolby Digital will not result in better audio if configuring the source device to decode it and output it as PCM. All you've done is change the device doing the decoding from the AV receiver to the source device.
You may find this informative:
Which is best, sending PCM or bitstream from the player to the A/V receiver? I have reviewed many posts in the A/V forums and other areas that don't seem to give a definitive answer. I have an Onkyo TX-SR608 AVR and an LG Blu-ray player capable of decoding DTS and Dolby lossless audio. I view...
www.soundandvision.com
and:
Blu-ray Disc players provide several audio output setting options. The two most important are the Bitstream and PCM settings. Find out what these settings do.
www.lifewire.com
PCM isn't technically an audio format and more a way of conveying digital data. It can convey data associated with audio that has a higher bitrate and sample rate than lossy formats, but only if the media you are accessing the audio from includes a PCM encoded soundtrack encoded with the additional information not present with the lossy compressed Dolby Digital variant of that same soundtrack. Converting the Dolby Dogital variant using the source device will not result in better audio.
You may also find this thread of interest:
An Attempt to Explain High Definition Audio & Some Other Stuff High Definition Audio Blu-Ray brings with it new high definition sound formats to match its high quality pictures and video. Sound can be stored on a disc in a number of ways: • Lossless Uncompressed (no data lost)...
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