Dialogic IMA ADPCM - Revision history

Lord Nightmare: further clarification

2025-10-22T23:11:00Z

further clarification

← Older revision		Revision as of 16:11, 22 October 2025
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	* A different, smaller step table is used (refer to Appendix A for the table). The table contains 49 values ranging from indices 0..48.		* A different, smaller step table is used (refer to Appendix A for the table). The table contains 49 values ranging from indices 0..48.
	* The predictor is always initialized to 0 at the start of decoding.		* The predictor is always initialized to 0 at the start of decoding.
	* The index is always initialized to index 0 ~~(value of 16)~~ at the start of decoding.		* The step table index is always initialized to index 0 at the start of decoding.
	* When the index is modified by the ADPCM delta, it should be clamped within the 0..48 range, rather than 0..88.		* When the index is modified by the ADPCM delta, it should be clamped within the 0..48 range, rather than 0..88.
	* When the diff is applied to the predictor, it should be clamped within a signed 12-bit range (-2048..2047) rather than a signed 16-bit range.		* When the diff is applied to the predictor, it should be clamped within a signed 12-bit range (-2048..2047) rather than a signed 16-bit range.

2025-10-22T23:10:02Z

fix an incorrect piece of information about the initial index value

← Older revision		Revision as of 16:10, 22 October 2025
Line 12:		Line 12:
	* A different, smaller step table is used (refer to Appendix A for the table). The table contains 49 values ranging from indices 0..48.		* A different, smaller step table is used (refer to Appendix A for the table). The table contains 49 values ranging from indices 0..48.
	* The predictor is always initialized to 0 at the start of decoding.		* The predictor is always initialized to 0 at the start of decoding.
	* The index is always initialized to 16 at the start of decoding.		* The index is always initialized to index 0 (value of 16) at the start of decoding.
	* When the index is modified by the ADPCM delta, it should be clamped within the 0..48 range, rather than 0..88.		* When the index is modified by the ADPCM delta, it should be clamped within the 0..48 range, rather than 0..88.
	* When the diff is applied to the predictor, it should be clamped within a signed 12-bit range (-2048..2047) rather than a signed 16-bit range.		* When the diff is applied to the predictor, it should be clamped within a signed 12-bit range (-2048..2047) rather than a signed 16-bit range.

2020-01-03T00:50:42Z

note about MSM5205 not saturating its accumulator, add more OKI chips, add link to datasheet

← Older revision		Revision as of 17:50, 2 January 2020
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	== Hardware Implementations ==		== Hardware Implementations ==
	The following ICs can decode this codec:		The following ICs can decode this codec:
	* OKI MSM5205		* OKI MSM5205 [dec] (Note that this particular chip, unlike any of the other OKI ADPCM decoder/codec chips, does not saturate the accumulator at its limits)
	* OKI MSM6295		* OKI MSM5218 [codec]
			* OKI MSM6295 [dec]
			* OKI MSM6585

			[[https://console5.com/techwiki/images/f/f8/MSM5205.pdf MSM5205/MSM5218 Datasheet]]

2017-10-30T06:16:44Z

better format for the hardware implementations

← Older revision		Revision as of 23:16, 29 October 2017
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	== Hardware Implementations ==		== Hardware Implementations ==
	The ~~OKI MSM5205 and MSM6295 ADPCM player chips~~ can ~~hardware-~~decode ~~data encoded in~~ this codec~~. They are commonly found on arcade games.~~		The following ICs can decode this codec:
			* OKI MSM5205
			* OKI MSM6295

2017-10-30T03:42:43Z

add note about hardware decoders for OKI/Dialogic IMA ADPCM

← Older revision		Revision as of 20:42, 29 October 2017
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	494, 544, 598, 658, 724, 796, 876, 963, 1060, 1166, 1282, 1411, 1552		494, 544, 598, 658, 724, 796, 876, 963, 1060, 1166, 1282, 1411, 1552
	};		};

			== Hardware Implementations ==
			The OKI MSM5205 and MSM6295 ADPCM player chips can hardware-decode data encoded in this codec. They are commonly found on arcade games.

2012-12-06T11:19:18Z

← Older revision		Revision as of 04:19, 6 December 2012
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	[[Category:ADPCM Audio Codecs]]		[[Category:ADPCM Audio Codecs]]
	[[Category:IMA ADPCM Audio Codecs]]		[[Category:IMA ADPCM Audio Codecs]]
	~~[[Category:Formats missing in FFmpeg]]~~

2009-01-05T12:07:19Z

← Older revision		Revision as of 05:07, 5 January 2009
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	* Microsoft Audio ID: 0x0010		* Microsoft Audio ID: 0x0010
	* Extension: vox		* Extension: vox, oki
	* Company: [[Dialogic]]		* Company: [[Dialogic]], Oki Electric Industry
	* Official Specification: http://multimedia.cx/mirror/dialogic-adpcm.pdf		* Official Specification: http://multimedia.cx/mirror/dialogic-adpcm.pdf

2009-01-05T10:01:03Z

2007-10-25T01:31:23Z

add mirrored PDF

← Older revision		Revision as of 18:31, 24 October 2007
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	* Extension: vox		* Extension: vox
	* Company: [[Dialogic]]		* Company: [[Dialogic]]
			* Official Specification: http://multimedia.cx/mirror/dialogic-adpcm.pdf

	Dialogic ADPCM is a variation of the standard [[IMA ADPCM]] algorithm that is optimized for monaural voice data. The encoder operates on 12-bit input samples and outputs 4-bit encoding for each sample. This yields a 3:1 compression ratio.		Dialogic ADPCM is a variation of the standard [[IMA ADPCM]] algorithm that is optimized for monaural voice data. The encoder operates on 12-bit input samples and outputs 4-bit encoding for each sample. This yields a 3:1 compression ratio.

2007-04-13T21:01:15Z

Add to formats missing in FFmpeg category.

← Older revision		Revision as of 14:01, 13 April 2007
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	[[Category:ADPCM Audio Codecs]]		[[Category:ADPCM Audio Codecs]]
	[[Category:IMA ADPCM Audio Codecs]]		[[Category:IMA ADPCM Audio Codecs]]
			[[Category:Formats missing in FFmpeg]]