roeville
12th February 2010, 13:48
What is the difference between these two PCM media subtypes:
MEDIASUBTYPE_DVD_LPCM_AUDIO
MEDIASUBTYPE_PCM
I want to copy PCM audio from a DVD video disk to an AVI file, but it seems that there must be a difference between these 2 PCM types because an exact copy of the bytes to an AVI file results in an AVI file which plays white noise.
I had to specify media subtype MEDASUBTYPE_PCM for the AVI file otherwise it will not play at all, but obviously these 2 formats are just not the same.
I'm pretty sure I have the media type structure set correctly because just changing to MEDIASUBTYPE_DVD_LPCM_AUDIO allows the audio to play OK connected to the DS audio renderer (but AVI Mux will not accept this type, only MEDIASUBTYPE_PCM).
Also, Microsoft's MPEG audio decoder in Windows 7 accepts MEDIASUBTYPE_DVD_LPCM_AUDIO as input, and outputs MEDASUBTYPE_PCM, so everything seems to point to these two types being different.
Is conversion between the 2 just a simple matter of swapping bytes around or is it more complicated?
MEDIASUBTYPE_DVD_LPCM_AUDIO
MEDIASUBTYPE_PCM
I want to copy PCM audio from a DVD video disk to an AVI file, but it seems that there must be a difference between these 2 PCM types because an exact copy of the bytes to an AVI file results in an AVI file which plays white noise.
I had to specify media subtype MEDASUBTYPE_PCM for the AVI file otherwise it will not play at all, but obviously these 2 formats are just not the same.
I'm pretty sure I have the media type structure set correctly because just changing to MEDIASUBTYPE_DVD_LPCM_AUDIO allows the audio to play OK connected to the DS audio renderer (but AVI Mux will not accept this type, only MEDIASUBTYPE_PCM).
Also, Microsoft's MPEG audio decoder in Windows 7 accepts MEDIASUBTYPE_DVD_LPCM_AUDIO as input, and outputs MEDASUBTYPE_PCM, so everything seems to point to these two types being different.
Is conversion between the 2 just a simple matter of swapping bytes around or is it more complicated?