Indeo Audio
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- Format: 0x402
- Company: Intel, now Ligos
- Samples: http://samples.mplayerhq.hu/A-codecs/Indeo_audio/
Related to the Intel Music Coder but with different codebooks and bitstream format.
Header format
bit 0 - should be zero bit 1 - should be zero bit 2 - stereo flag bits 3-8 - block size code bit 9 - codebook set selector (0 - no escapes, 1 - with escapes) bit 10 - codebook selector bit 11 - use raw coding bit 12 - SNR offset (-30 or -10)
Block size code:
0, 34-50 - (block_size + 14) 16-bit words 33 - 32 words 1-32 - (block_size + 15) words 51-63 - invalid value
Levels
There are 32 levels, coded with either one of codebooks or in raw form.
Decoding Huffman-coded levels is the same as in Intel Music Coder but with different tables.
Raw form:
1st coefficient - 5 bits 2nd coefficient - 7 bits others - 4 bits per coefficient