Indeo Audio
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| Revision as of 13:35, 12 October 2006 DonDiego (Talk | contribs) (linkify IMC) ← Previous diff |
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| * Samples: http://samples.mplayerhq.hu/A-codecs/Indeo_audio/ | * Samples: http://samples.mplayerhq.hu/A-codecs/Indeo_audio/ | ||
| - | Probably related to the [[Intel Music Coder]]. | + | 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 | ||
| [[Category:Audio Codecs]] | [[Category:Audio Codecs]] | ||
| [[Category:Undiscovered Audio Codecs]] | [[Category:Undiscovered Audio Codecs]] | ||
Revision as of 10:25, 20 May 2012
- 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
