EA Command And Conquer 3 Audio Codec
- Extension: .cdata
- Website: http://www.cncnz.com/games/cnc3/demo/
- Company: Electronic Arts
- Samples: http://samples.mplayerhq.hu/game-formats/cc3-audio/
This format is found on certain .cdata files used for sound effects/voice inside the *.BIG resource files of the new Command & Conquer 3 Demo. Using a program such as OS Big Editor 0.4 you can open the DemoStreams.big file from the C&C3 Demo and extract any .cdata file from the "data\global_demo_common\cdata" folder.
The file begins with a 16-byte header, which is then followed by codec specific data. All numbers are encoded in big endian.
bytes 0-1 codec type 0x0000 EA Layer 3 0x0400 EA ADPCM XAS mono 0x0404 EA ADPCM XAS stero 0x040c EA ADPCM XAS quad 0x0504 EALayer3 MPEG Layer 3 audio variant bytes 2-3 sample rate bytes 4-7 total samples bytes 8-11 total file size (bytes) bytes 12-16 total samples
EA ADPCM XAS
XAS is a variation on the Electronic Arts XA codec that uses four independant PCM deltas.
Compressed audio data is arranged in 76-byte blocks that follow sequentially after the header. Each block corresponds to 128 audio samples. In files with stereo audio, the blocks alternate between left and right channels. For example, the first block is for the first channel, the next is for the second channel and so on.
Each block beings with a 16-byte header, and is followed by 15 x 4-byte compressed audio blobs.
Thanks to KMX at Derelict Studios for finding out the initial information on this format as it applies to C&C3.