Lossless Audio in Games

[WriteSimply]

Originally Posted by zweet77

I think that cutscenes and musical scores are part of a final mix that was made for the game.

Cut-scenes and scores are pre-mixed audio. There's no need to mix them on the fly, even if the video is not pre-rendered.

So for games like those It is the ps3 that is decoding it to pcm.

You still don't understand the concept of mixing the audio. So let's do a reverse engineering. Take any game audio that has is output via optical in Dolby Digital and DTS. Before your receiver can decode that DD/DTS bitstream into 5.1/7.1 channels, it has to RECEIVE that un-decoded bitstream first. That bitstream comes from the PS3, which ENCODES the DD/DTS bitstream on the fly. But how do you think it does the encoding? Do you think all of the sound effects of gunshots, grunts, cars passing by are pre-mixed and pre-encoded?

Like I said earlier, it is easier for the PS3 to assemble the audio elements in PCM and output it as PCM than having to allocate processing power to encode 5.1/7.1 the lossy DD/DTS mix. Plus with PCM, you get uncompressed lossless audio.

Originally Posted by Kenshiro

My question is concerning the 50+ PS3 games that support discrete 7.1 audio.. If there is only one audio track on the disc that is compressed, wouldn't the developers have to be using some type of lossy 7.1 compression codec like Dolby Digital Plus or DTS-HD, or are they allowed to just add two more channels to a standard DD 5.1 or a DTS 5.1 track? With all the extra space on the Blu-ray, wouldn't it be easier to just use 7.1 LPCM which is free? I'm curious...

DD+ and DTS HD of over 5.1 can't be transmitted over optical because it consumes too much bandwith. DD and DTS have a maximum of 6.1 channels (DTS-ES Discrete has a discrete channel while DD Ex has a matrixed channel) that can be transmitted over optical.

For games supporting 7.1 audio, the extra channel is just mixed into the 5.1 mix for optical playback. If you're outputting multichannel PCM via HDMI, then you get the full 7.1 audio.


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