DVI IMA ADPCM - Revision history

Lord Nightmare: formatting

2018-10-12T02:30:52Z

formatting

← Older revision		Revision as of 19:30, 11 October 2018
Line 3:		Line 3:
	== DVI4 ==		== DVI4 ==

	The [https://www.freesoft.org/CIE/RFC/1890/10.htm DVI4] codec, as defined in [https://www.freesoft.org/CIE/RFC/1890/index.htm RFC1890] is a variant of [[IMA ADPCM]] ~~where~~, unlike [[IMA ADPCM]] where the header stores the first sample, in DVI4 ~~the header stores the initial predictor state~~.		The [https://www.freesoft.org/CIE/RFC/1890/10.htm DVI4] codec, as defined in [https://www.freesoft.org/CIE/RFC/1890/index.htm RFC1890] is a variant of [[IMA ADPCM]].
			In DVI4 the block header stores the initial predictor state, unlike [[IMA ADPCM]] where the block header stores the first sample.
			Otherwise, DVI4 is decoded identically to [[IMA ADPCM]].

	[[Category:Audio Codecs]]		[[Category:Audio Codecs]]
	[[Category:ADPCM Audio Codecs]]		[[Category:ADPCM Audio Codecs]]
	[[Category:IMA ADPCM Audio Codecs]]		[[Category:IMA ADPCM Audio Codecs]]

Lord Nightmare: fix heading

2018-10-12T02:29:08Z

fix heading

← Older revision		Revision as of 19:29, 11 October 2018
Line 1:		Line 1:
	According to the [[XAnim]] multimedia application, there are two variants of DVI [[IMA ADPCM]], both of which are encoded and decoded with the IMA ADPCM algorithm. The original variant encodes the top nibble of a byte first, then the bottom nibble. The revised variant has the opposite encoding order.		According to the [[XAnim]] multimedia application, there are two variants of DVI [[IMA ADPCM]], both of which are encoded and decoded with the IMA ADPCM algorithm. The original variant encodes the top nibble of a byte first, then the bottom nibble. The revised variant has the opposite encoding order.

	- DVI4 -		== DVI4 ==

	The [https://www.freesoft.org/CIE/RFC/1890/10.htm DVI4] codec, as defined in [https://www.freesoft.org/CIE/RFC/1890/index.htm RFC1890] is a variant of [[IMA ADPCM]] where, unlike [[IMA ADPCM]] where the header stores the first sample, in DVI4 the header stores the initial predictor state.		The [https://www.freesoft.org/CIE/RFC/1890/10.htm DVI4] codec, as defined in [https://www.freesoft.org/CIE/RFC/1890/index.htm RFC1890] is a variant of [[IMA ADPCM]] where, unlike [[IMA ADPCM]] where the header stores the first sample, in DVI4 the header stores the initial predictor state.

Lord Nightmare: add description of DVI4 codec and links

2018-10-12T02:28:39Z

add description of DVI4 codec and links

← Older revision		Revision as of 19:28, 11 October 2018
Line 1:		Line 1:
	According to the [[XAnim]] multimedia application, there are two variants of DVI [[IMA ADPCM]], both of which are encoded and decoded with the IMA ADPCM algorithm. The original variant encodes the top nibble of a byte first, then the bottom nibble. The revised variant has the opposite encoding order.		According to the [[XAnim]] multimedia application, there are two variants of DVI [[IMA ADPCM]], both of which are encoded and decoded with the IMA ADPCM algorithm. The original variant encodes the top nibble of a byte first, then the bottom nibble. The revised variant has the opposite encoding order.

			- DVI4 -
			The [https://www.freesoft.org/CIE/RFC/1890/10.htm DVI4] codec, as defined in [https://www.freesoft.org/CIE/RFC/1890/index.htm RFC1890] is a variant of [[IMA ADPCM]] where, unlike [[IMA ADPCM]] where the header stores the first sample, in DVI4 the header stores the initial predictor state.

	[[Category:Audio Codecs]]		[[Category:Audio Codecs]]
	[[Category:ADPCM Audio Codecs]]		[[Category:ADPCM Audio Codecs]]
	[[Category:IMA ADPCM Audio Codecs]]		[[Category:IMA ADPCM Audio Codecs]]

Lord Nightmare: I need to rethink this...

2017-10-30T06:09:41Z

I need to rethink this...

← Older revision		Revision as of 23:09, 29 October 2017
Line 1:		Line 1:
	According to the [[XAnim]] multimedia application, there are two variants of DVI [[IMA ADPCM]], both of which are encoded and decoded with the IMA ADPCM algorithm. The original variant encodes the top nibble of a byte first, then the bottom nibble. The revised variant has the opposite encoding order.		According to the [[XAnim]] multimedia application, there are two variants of DVI [[IMA ADPCM]], both of which are encoded and decoded with the IMA ADPCM algorithm. The original variant encodes the top nibble of a byte first, then the bottom nibble. The revised variant has the opposite encoding order.

	[[IMA ADPCM]] and [[Microsoft IMA ADPCM]] are both the same codec, an implementation of the Intel/DVI(R) IMA ADPCM standard, the only difference being encapsulation around (and nybble order of) the ADPCM data. The [[IMA ADPCM]] standard did not specify headers (RIFF/WAV/AU/etc) nor did it specify a nybble order for packing 4-bit ADPCM nybbles to a byte, while the [[Microsoft IMA ADPCM]] implementation does. It is possible that other [[IMA ADPCM]] implementations, such as the one in .AU and .AIFF files, is different in this regard.

	[[Category:Audio Codecs]]		[[Category:Audio Codecs]]
	[[Category:ADPCM Audio Codecs]]		[[Category:ADPCM Audio Codecs]]
	[[Category:IMA ADPCM Audio Codecs]]		[[Category:IMA ADPCM Audio Codecs]]

Lord Nightmare: add more information

2017-10-30T03:07:25Z

add more information

← Older revision		Revision as of 20:07, 29 October 2017
Line 1:		Line 1:
	According to the [[XAnim]] multimedia application, there are two variants of DVI [[IMA ADPCM]], both of which are encoded and decoded with the IMA ADPCM algorithm. The original variant encodes the top nibble of a byte first, then the bottom nibble. The revised variant has the opposite encoding order.		According to the [[XAnim]] multimedia application, there are two variants of DVI [[IMA ADPCM]], both of which are encoded and decoded with the IMA ADPCM algorithm. The original variant encodes the top nibble of a byte first, then the bottom nibble. The revised variant has the opposite encoding order.

	[IMA ADPCM] and [Microsoft IMA ADPCM] are both the same codec, an implementation of the ~~IMA~~/DVI ADPCM standard, the only difference being encapsulation around the ADPCM data. The [IMA ADPCM] standard did not specify RIFF/WAV ~~file headers~~, while the [Microsoft IMA ADPCM] implementation does.		[[IMA ADPCM]] and [[Microsoft IMA ADPCM]] are both the same codec, an implementation of the Intel/DVI(R) IMA ADPCM standard, the only difference being encapsulation around (and nybble order of) the ADPCM data. The [[IMA ADPCM]] standard did not specify headers (RIFF/WAV/AU/etc) nor did it specify a nybble order for packing 4-bit ADPCM nybbles to a byte, while the [[Microsoft IMA ADPCM]] implementation does. It is possible that other [[IMA ADPCM]] implementations, such as the one in .AU and .AIFF files, is different in this regard.

	[[Category:Audio Codecs]]		[[Category:Audio Codecs]]
	[[Category:ADPCM Audio Codecs]]		[[Category:ADPCM Audio Codecs]]
	[[Category:IMA ADPCM Audio Codecs]]		[[Category:IMA ADPCM Audio Codecs]]

Lord Nightmare: add info about the fact that DVI_IMA_ADPCM, IMA_ADPCM and Microsoft_IMA_ADPCM are all fundamentally the same codec

2017-10-30T02:51:56Z

add info about the fact that DVI_IMA_ADPCM, IMA_ADPCM and Microsoft_IMA_ADPCM are all fundamentally the same codec

← Older revision		Revision as of 19:51, 29 October 2017
Line 1:		Line 1:
	According to the [[XAnim]] multimedia application, there are two variants of DVI [[IMA ADPCM]], both of which are encoded and decoded with the IMA ADPCM algorithm. The original variant encodes the top nibble of a byte first, then the bottom nibble. The revised variant has the opposite encoding order.		According to the [[XAnim]] multimedia application, there are two variants of DVI [[IMA ADPCM]], both of which are encoded and decoded with the IMA ADPCM algorithm. The original variant encodes the top nibble of a byte first, then the bottom nibble. The revised variant has the opposite encoding order.

			[IMA ADPCM] and [Microsoft IMA ADPCM] are both the same codec, an implementation of the IMA/DVI ADPCM standard, the only difference being encapsulation around the ADPCM data. The [IMA ADPCM] standard did not specify RIFF/WAV file headers, while the [Microsoft IMA ADPCM] implementation does.

	[[Category:Audio Codecs]]		[[Category:Audio Codecs]]
	[[Category:ADPCM Audio Codecs]]		[[Category:ADPCM Audio Codecs]]
	[[Category:IMA ADPCM Audio Codecs]]		[[Category:IMA ADPCM Audio Codecs]]

DonDiego: I assume "but of which" was a typo...

2006-02-05T01:34:41Z

I assume "but of which" was a typo...

← Older revision		Revision as of 18:34, 4 February 2006
Line 1:		Line 1:
	According to the [[XAnim]] multimedia application, there are two variants of DVI [[IMA ADPCM]], ~~but~~ of which are encoded and decoded with the IMA ADPCM algorithm. The original variant encodes the top nibble of a byte first, then the bottom nibble. The revised variant has the opposite encoding order.		According to the [[XAnim]] multimedia application, there are two variants of DVI [[IMA ADPCM]], both of which are encoded and decoded with the IMA ADPCM algorithm. The original variant encodes the top nibble of a byte first, then the bottom nibble. The revised variant has the opposite encoding order.

	[[Category:Audio Codecs]]		[[Category:Audio Codecs]]
	[[Category:ADPCM Audio Codecs]]		[[Category:ADPCM Audio Codecs]]
	[[Category:IMA ADPCM Audio Codecs]]		[[Category:IMA ADPCM Audio Codecs]]

Multimedia Mike at 20:41, 4 February 2006

2006-02-04T20:41:49Z

New page

According to the [[XAnim]] multimedia application, there are two variants of DVI [[IMA ADPCM]], but of which are encoded and decoded with the IMA ADPCM algorithm. The original variant encodes the top nibble of a byte first, then the bottom nibble. The revised variant has the opposite encoding order.

[[Category:Audio Codecs]]
[[Category:ADPCM Audio Codecs]]
[[Category:IMA ADPCM Audio Codecs]]