Electronic Arts MicroTalk

• Company: Electronic Arts
• Decoding: https://github.com/daddesio/utkencode
• Samples: http://niotso.org/utalk/

EA MicroTalk (also UTalk or UTK) is a linear-predictive speech codec used in various games by Electronic Arts. The earliest known game to use it is Beasts & Bumpkins (1997). The codec has a bandwidth of 11.025kHz (sampling rate 22.05kHz) and frame size of 20ms (432 samples) and only supports mono. It is typically encoded at 32 kbit/s.

The codec was reverse-engineered by trass3r on August 05, 2010 and was later analyzed by Andrew D'Addesio on January 12, 2012.

MicroTalk has been seen in several containers, depending on the game:

• PT/.m10 (Beasts and Bumpkins)
• Maxis UTK (The Sims Online, SimCity 4)
• SCxl (FIFA 2001 PS2, FIFA 2002 PS2)

Variants

There are a few variants of MicroTalk:

• MicroTalk 10:1 (codec_id=0x04 in EA SCxl) and MicroTalk 5:1 (codec_id=0x16) are really the same codec; the encoder simply chooses different compression parameters (reduced_bw is enabled in 10:1 and disabled in 5:1). MicroTalk 10:1 is typically encoded at 32kbit/s; 5:1 is encoded at 64kbit/s.
• MicroTalk Revision 3 (codec_revision=3 in SCxl) is a variant which supports raw PCM samples.

Huffman tables

Normal model (Table 0):

Huffman code	Output command	Meaning	Next model
0 0	4	Insert one 0.0f	MDL_NORMAL
0 1	5	Insert one -1.0f	MDL_NORMAL
1 0	6	Insert one +1.0f	MDL_NORMAL
1 1 0 0	9	Insert one -2.0f	MDL_LARGEPULSE
1 1 0 1	10	Insert one +2.0f	MDL_LARGEPULSE
1 1 1 0 0	13	Insert one -3.0f	MDL_LARGEPULSE
1 1 1 0 1	14	Insert one +3.0f	MDL_LARGEPULSE
1 1 1 1 0 0	17	Insert one -4.0f	MDL_LARGEPULSE
1 1 1 1 0 1	18	Insert one +4.0f	MDL_LARGEPULSE
1 1 1 1 1 0 0	21	Insert one -5.0f	MDL_LARGEPULSE
1 1 1 1 1 0 1	22	Insert one +5.0f	MDL_LARGEPULSE
1 1 1 1 1 1 0 0	25	Insert one -6.0f	MDL_LARGEPULSE
1 1 1 1 1 1 0 1	26	Insert one +6.0f	MDL_LARGEPULSE
1 1 1 1 1 1 1 0	0	Insert a pulse with magnitude >= 7.0f	MDL_LARGEPULSE
1 1 1 1 1 1 1 1	2	Insert between 7 and 70 0.0fs	MDL_NORMAL

Large-pulse model (Table 1):

Huffman code	Output command	Meaning	Next model
0 0	4	Insert one 0.0f	MDL_NORMAL
0 1 0	7	Insert one -1.0f	MDL_NORMAL
0 1 1	8	Insert one +1.0f	MDL_NORMAL
1 0 0	11	Insert one -2.0f	MDL_LARGEPULSE
1 0 1	12	Insert one +2.0f	MDL_LARGEPULSE
1 1 0 0	15	Insert one -3.0f	MDL_LARGEPULSE
1 1 0 1	16	Insert one +3.0f	MDL_LARGEPULSE
1 1 1 0 0	19	Insert one -4.0f	MDL_LARGEPULSE
1 1 1 0 1	20	Insert one +4.0f	MDL_LARGEPULSE
1 1 1 1 0 0	23	Insert one -5.0f	MDL_LARGEPULSE
1 1 1 1 0 1	24	Insert one +5.0f	MDL_LARGEPULSE
1 1 1 1 1 0 0	27	Insert one -6.0f	MDL_LARGEPULSE
1 1 1 1 1 0 1	28	Insert one +6.0f	MDL_LARGEPULSE
1 1 1 1 1 1 0	1	Insert a pulse with magnitude >= 7.0f	MDL_LARGEPULSE
1 1 1 1 1 1 1	3	Insert between 7 and 70 0.0fs	MDL_NORMAL