X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=modules%2Fcodec%2Fadpcm.c;h=6c4d116a68d5d8a20213ae78a310bfb6ab277b4e;hb=8229bf31c8d590c8e5c176ddc905d11a323c53e7;hp=ce980da5c6cc6a0cfc7f667e13a6df7ca0d263c9;hpb=81b7c54562bbdb33e649686e170ce281d48975f6;p=vlc diff --git a/modules/codec/adpcm.c b/modules/codec/adpcm.c index ce980da5c6..6c4d116a68 100644 --- a/modules/codec/adpcm.c +++ b/modules/codec/adpcm.c @@ -2,15 +2,15 @@ * adpcm.c : adpcm variant audio decoder ***************************************************************************** * Copyright (C) 2001, 2002 VideoLAN - * $Id: adpcm.c,v 1.5 2003/01/07 21:49:01 fenrir Exp $ + * $Id: adpcm.c,v 1.10 2003/03/11 23:56:40 fenrir Exp $ * * Authors: Laurent Aimar - * + * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. - * + * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the @@ -41,22 +41,25 @@ #define ADPCM_IMA_QT 1 #define ADPCM_IMA_WAV 2 #define ADPCM_MS 3 +#define ADPCM_DK3 4 +#define ADPCM_DK4 5 typedef struct adec_thread_s { int i_codec; WAVEFORMATEX *p_wf; - - /* The bit stream structure handles the PES stream at the bit level */ - bit_stream_t bit_stream; + int i_block; uint8_t *p_block; int i_samplesperblock; - + + uint8_t *p_buffer; /* buffer for gather pes */ \ + int i_buffer; /* bytes present in p_buffer */ + /* Input properties */ decoder_fifo_t *p_fifo; - + /* Output properties */ aout_instance_t * p_aout; /* opaque */ aout_input_t * p_aout_input; /* opaque */ @@ -75,8 +78,11 @@ static void DecodeThread ( adec_thread_t * ); static void EndThread ( adec_thread_t * ); -static void DecodeAdpcmMs( adec_thread_t *, aout_buffer_t * ); -static void DecodeAdpcmImaWav( adec_thread_t *, aout_buffer_t * ); +static void DecodeAdpcmMs ( adec_thread_t *, aout_buffer_t * ); +static void DecodeAdpcmImaWav ( adec_thread_t *, aout_buffer_t * ); +static void DecodeAdpcmImaQT ( adec_thread_t *, aout_buffer_t * ); +static void DecodeAdpcmDk4 ( adec_thread_t *, aout_buffer_t * ); +static void DecodeAdpcmDk3 ( adec_thread_t *, aout_buffer_t * ); /***************************************************************************** * Module descriptor @@ -97,7 +103,7 @@ static int pi_channels_maps[6] = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT | AOUT_CHAN_CENTER, AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT | AOUT_CHAN_REARLEFT | AOUT_CHAN_REARLEFT, AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT | AOUT_CHAN_CENTER - | AOUT_CHAN_REARLEFT | AOUT_CHAN_REARLEFT + | AOUT_CHAN_REARLEFT | AOUT_CHAN_REARLEFT }; /* Various table from http://www.pcisys.net/~melanson/codecs/adpcm.txt */ @@ -146,18 +152,18 @@ static int i_adaptation_coeff2[7] = static int OpenDecoder( vlc_object_t *p_this ) { decoder_fifo_t *p_fifo = (decoder_fifo_t*) p_this; - + switch( p_fifo->i_fourcc ) - { -// case VLC_FOURCC('i','m','a', '4'): /* IMA ADPCM */ + { + case VLC_FOURCC('i','m','a', '4'): /* IMA ADPCM */ case VLC_FOURCC('m','s',0x00,0x02): /* MS ADPCM */ case VLC_FOURCC('m','s',0x00,0x11): /* IMA ADPCM */ -// case VLC_FOURCC('m','s',0x00,0x61): /* Duck DK4 ADPCM */ -// case VLC_FOURCC('m','s',0x00,0x62): /* Duck DK3 ADPCM */ + case VLC_FOURCC('m','s',0x00,0x61): /* Duck DK4 ADPCM */ + case VLC_FOURCC('m','s',0x00,0x62): /* Duck DK3 ADPCM */ p_fifo->pf_run = RunDecoder; return VLC_SUCCESS; - + default: return VLC_EGENERIC; } @@ -179,7 +185,7 @@ static int RunDecoder( decoder_fifo_t *p_fifo ) return( -1 ); } memset( p_adec, 0, sizeof( adec_thread_t ) ); - + p_adec->p_fifo = p_fifo; if( InitThread( p_adec ) != 0 ) @@ -211,11 +217,11 @@ static int RunDecoder( decoder_fifo_t *p_fifo ) #define FREE( p ) if( p ) free( p ); p = NULL #define GetWLE( p ) \ - ( *(u8*)(p) + ( *((u8*)(p)+1) << 8 ) ) + ( *(uint8_t*)(p) + ( *((uint8_t*)(p)+1) << 8 ) ) #define GetDWLE( p ) \ - ( *(u8*)(p) + ( *((u8*)(p)+1) << 8 ) + \ - ( *((u8*)(p)+2) << 16 ) + ( *((u8*)(p)+3) << 24 ) ) + ( *(uint8_t*)(p) + ( *((uint8_t*)(p)+1) << 8 ) + \ + ( *((uint8_t*)(p)+2) << 16 ) + ( *((uint8_t*)(p)+3) << 24 ) ) /***************************************************************************** * InitThread: initialize data before entering main loop @@ -241,12 +247,14 @@ static int InitThread( adec_thread_t * p_adec ) p_adec->i_codec = ADPCM_MS; break; case VLC_FOURCC('m','s',0x00,0x61): /* Duck DK4 ADPCM */ + p_adec->i_codec = ADPCM_DK4; + break; case VLC_FOURCC('m','s',0x00,0x62): /* Duck DK3 ADPCM */ - p_adec->i_codec = 0; + p_adec->i_codec = ADPCM_DK3; break; } - if( p_adec->p_wf->nChannels < 1 || + if( p_adec->p_wf->nChannels < 1 || p_adec->p_wf->nChannels > 2 ) { msg_Err( p_adec->p_fifo, "bad channels count(1-2)" ); @@ -256,17 +264,17 @@ static int InitThread( adec_thread_t * p_adec ) { if( p_adec->i_codec == ADPCM_IMA_QT ) { - p_adec->i_block = 34; + p_adec->i_block = 34 * p_adec->p_wf->nChannels; } else { p_adec->i_block = 1024; // XXX FIXME } - msg_Err( p_adec->p_fifo, - "block size undefined, using %d default", + msg_Warn( p_adec->p_fifo, + "block size undefined, using %d default", p_adec->i_block ); } - p_adec->p_block = malloc( p_adec->i_block ); + p_adec->p_block = NULL; /* calculate samples per block */ switch( p_adec->i_codec ) @@ -275,34 +283,44 @@ static int InitThread( adec_thread_t * p_adec ) p_adec->i_samplesperblock = 64; break; case ADPCM_IMA_WAV: - p_adec->i_samplesperblock = + p_adec->i_samplesperblock = 2 * ( p_adec->i_block - 4 * p_adec->p_wf->nChannels )/ p_adec->p_wf->nChannels; break; case ADPCM_MS: - p_adec->i_samplesperblock = - 2 * ( p_adec->i_block - 7 * p_adec->p_wf->nChannels ) / + p_adec->i_samplesperblock = + 2 * ( p_adec->i_block - 7 * p_adec->p_wf->nChannels ) / p_adec->p_wf->nChannels + 2; break; + case ADPCM_DK4: + p_adec->i_samplesperblock = + 2 * ( p_adec->i_block - 4 * p_adec->p_wf->nChannels ) / + p_adec->p_wf->nChannels + 1; + break; + case ADPCM_DK3: + p_adec->p_wf->nChannels = 2; + p_adec->i_samplesperblock = ( 4 * ( p_adec->i_block - 16 ) + 2 )/ 3; + break; default: - p_adec->i_samplesperblock = 0; + msg_Err( p_adec->p_fifo, "unknown adpcm variant" ); + return( -1 ); } - + msg_Dbg( p_adec->p_fifo, "format: samplerate:%dHz channels:%d bits/sample:%d blockalign:%d samplesperblock %d", p_adec->p_wf->nSamplesPerSec, p_adec->p_wf->nChannels, - p_adec->p_wf->wBitsPerSample, + p_adec->p_wf->wBitsPerSample, p_adec->p_wf->nBlockAlign, p_adec->i_samplesperblock ); - + //p_adec->output_format.i_format = VLC_FOURCC('s','1','6','l'); /* FIXME good way ? */ p_adec->output_format.i_format = AOUT_FMT_S16_NE; p_adec->output_format.i_rate = p_adec->p_wf->nSamplesPerSec; - p_adec->output_format.i_physical_channels = + p_adec->output_format.i_physical_channels = p_adec->output_format.i_original_channels = pi_channels_maps[p_adec->p_wf->nChannels]; p_adec->p_aout = NULL; @@ -320,70 +338,140 @@ static int InitThread( adec_thread_t * p_adec ) } /* Init the BitStream */ - InitBitstream( &p_adec->bit_stream, p_adec->p_fifo, - NULL, NULL ); +// InitBitstream( &p_adec->bit_stream, p_adec->p_fifo, +// NULL, NULL ); return( 0 ); } +static void GetPESData( uint8_t *p_buf, int i_max, pes_packet_t *p_pes ) +{ + int i_copy; + int i_count; + + data_packet_t *p_data; + + i_count = 0; + p_data = p_pes->p_first; + while( p_data != NULL && i_count < i_max ) + { + + i_copy = __MIN( p_data->p_payload_end - p_data->p_payload_start, + i_max - i_count ); + + if( i_copy > 0 ) + { + memcpy( p_buf, + p_data->p_payload_start, + i_copy ); + } + + p_data = p_data->p_next; + i_count += i_copy; + p_buf += i_copy; + } + + if( i_count < i_max ) + { + memset( p_buf, 0, i_max - i_count ); + } +} + /***************************************************************************** * DecodeThread: decodes a frame *****************************************************************************/ static void DecodeThread( adec_thread_t *p_adec ) { aout_buffer_t *p_aout_buffer; + pes_packet_t *p_pes; - /* get pts */ - CurrentPTS( &p_adec->bit_stream, &p_adec->pts, NULL ); - /* gather block */ - GetChunk( &p_adec->bit_stream, - p_adec->p_block, - p_adec->i_block ); + int i_frame_size; - /* get output buffer */ - if( p_adec->pts != 0 && p_adec->pts != aout_DateGet( &p_adec->date ) ) + /* **** Get a new frames from streams **** */ + do { - aout_DateSet( &p_adec->date, p_adec->pts ); - } - else if( !aout_DateGet( &p_adec->date ) ) - { - return; - } + input_ExtractPES( p_adec->p_fifo, &p_pes ); + if( !p_pes ) + { + p_adec->p_fifo->b_error = 1; + return; + } + if( p_pes->i_pts != 0 ) + { + p_adec->pts = p_pes->i_pts; + } + i_frame_size = p_pes->i_pes_size; - p_aout_buffer = aout_DecNewBuffer( p_adec->p_aout, - p_adec->p_aout_input, - p_adec->i_samplesperblock ); - if( !p_aout_buffer ) - { - msg_Err( p_adec->p_fifo, "cannot get aout buffer" ); - p_adec->p_fifo->b_error = 1; - return; - } - - p_aout_buffer->start_date = aout_DateGet( &p_adec->date ); - p_aout_buffer->end_date = aout_DateIncrement( &p_adec->date, - p_adec->i_samplesperblock ); + if( i_frame_size > 0 ) + { + if( p_adec->i_buffer < i_frame_size + 16 ) + { + FREE( p_adec->p_buffer ); + p_adec->p_buffer = malloc( i_frame_size + 16 ); + p_adec->i_buffer = i_frame_size + 16; + } - /* decode */ - - switch( p_adec->i_codec ) + GetPESData( p_adec->p_buffer, p_adec->i_buffer, p_pes ); + } + input_DeletePES( p_adec->p_fifo->p_packets_mgt, p_pes ); + + } while( i_frame_size <= 0 ); + + for( p_adec->p_block = p_adec->p_buffer; + i_frame_size >= p_adec->i_block; + p_adec->p_block += p_adec->i_block, i_frame_size -= p_adec->i_block ) { - case ADPCM_IMA_QT: - break; - case ADPCM_IMA_WAV: - DecodeAdpcmImaWav( p_adec, p_aout_buffer ); - break; - case ADPCM_MS: - DecodeAdpcmMs( p_adec, p_aout_buffer ); - break; - default: - break; - } + /* get output buffer */ + if( p_adec->pts != 0 && p_adec->pts != aout_DateGet( &p_adec->date ) ) + { + aout_DateSet( &p_adec->date, p_adec->pts ); + } + else if( !aout_DateGet( &p_adec->date ) ) + { + return; + } + p_adec->pts = 0; + + p_aout_buffer = aout_DecNewBuffer( p_adec->p_aout, + p_adec->p_aout_input, + p_adec->i_samplesperblock ); + if( !p_aout_buffer ) + { + msg_Err( p_adec->p_fifo, "cannot get aout buffer" ); + p_adec->p_fifo->b_error = 1; + return; + } + + p_aout_buffer->start_date = aout_DateGet( &p_adec->date ); + p_aout_buffer->end_date = aout_DateIncrement( &p_adec->date, + p_adec->i_samplesperblock ); + + /* decode */ + + switch( p_adec->i_codec ) + { + case ADPCM_IMA_QT: + DecodeAdpcmImaQT( p_adec, p_aout_buffer ); + break; + case ADPCM_IMA_WAV: + DecodeAdpcmImaWav( p_adec, p_aout_buffer ); + break; + case ADPCM_MS: + DecodeAdpcmMs( p_adec, p_aout_buffer ); + break; + case ADPCM_DK4: + DecodeAdpcmDk4( p_adec, p_aout_buffer ); + case ADPCM_DK3: + DecodeAdpcmDk3( p_adec, p_aout_buffer ); + default: + break; + } - /* **** Now we can output these samples **** */ - aout_DecPlay( p_adec->p_aout, p_adec->p_aout_input, p_aout_buffer ); + /* **** Now we can output these samples **** */ + aout_DecPlay( p_adec->p_aout, p_adec->p_aout_input, p_aout_buffer ); + } } @@ -398,8 +486,8 @@ static void EndThread (adec_thread_t *p_adec) } msg_Dbg( p_adec->p_fifo, "adpcm audio decoder closed" ); - - free( p_adec->p_block ); + + FREE( p_adec->p_buffer ); free( p_adec ); } #define CLAMP( v, min, max ) \ @@ -414,9 +502,12 @@ static void EndThread (adec_thread_t *p_adec) (v) |= ( *p_buffer ) << 8; p_buffer++; \ if( (v)&0x8000 ) (v) -= 0x010000; +/* + * MS + */ typedef struct adpcm_ms_channel_s { - int i_idelta; + int i_idelta; int i_sample1, i_sample2; int i_coeff1, i_coeff2; @@ -431,8 +522,8 @@ static int AdpcmMsExpandNibble(adpcm_ms_channel_t *p_channel, /* expand sign */ i_snibble = i_nibble - ( i_nibble&0x08 ? 0x10 : 0 ); - - i_predictor = ( p_channel->i_sample1 * p_channel->i_coeff1 + + + i_predictor = ( p_channel->i_sample1 * p_channel->i_coeff1 + p_channel->i_sample2 * p_channel->i_coeff2 ) / 256 + i_snibble * p_channel->i_idelta; @@ -441,7 +532,7 @@ static int AdpcmMsExpandNibble(adpcm_ms_channel_t *p_channel, p_channel->i_sample2 = p_channel->i_sample1; p_channel->i_sample1 = i_predictor; - p_channel->i_idelta = ( i_adaptation_table[i_nibble] * + p_channel->i_idelta = ( i_adaptation_table[i_nibble] * p_channel->i_idelta ) / 256; if( p_channel->i_idelta < 16 ) { @@ -449,8 +540,8 @@ static int AdpcmMsExpandNibble(adpcm_ms_channel_t *p_channel, } return( i_predictor ); } - -static void DecodeAdpcmMs( adec_thread_t *p_adec, + +static void DecodeAdpcmMs( adec_thread_t *p_adec, aout_buffer_t *p_aout_buffer) { uint8_t *p_buffer; @@ -459,7 +550,7 @@ static void DecodeAdpcmMs( adec_thread_t *p_adec, uint16_t *p_sample; int b_stereo; int i_block_predictor; - + p_buffer = p_adec->p_block; b_stereo = p_adec->p_wf->nChannels == 2 ? 1 : 0; @@ -480,7 +571,7 @@ static void DecodeAdpcmMs( adec_thread_t *p_adec, { GetWord( channel[1].i_idelta ); } - + GetWord( channel[0].i_sample1 ); if( b_stereo ) { @@ -513,15 +604,18 @@ static void DecodeAdpcmMs( adec_thread_t *p_adec, { *p_sample = AdpcmMsExpandNibble( &channel[0], (*p_buffer) >> 4); p_sample++; - - *p_sample = AdpcmMsExpandNibble( &channel[b_stereo ? 1 : 0], + + *p_sample = AdpcmMsExpandNibble( &channel[b_stereo ? 1 : 0], (*p_buffer)&0x0f); p_sample++; } - + } +/* + * IMA-WAV + */ typedef struct adpcm_ima_wav_channel_s { int i_predictor; @@ -552,7 +646,7 @@ static int AdpcmImaWavExpandNibble(adpcm_ima_wav_channel_t *p_channel, return( p_channel->i_predictor ); } -static void DecodeAdpcmImaWav( adec_thread_t *p_adec, +static void DecodeAdpcmImaWav( adec_thread_t *p_adec, aout_buffer_t *p_aout_buffer) { uint8_t *p_buffer; @@ -560,7 +654,7 @@ static void DecodeAdpcmImaWav( adec_thread_t *p_adec, int i_nibbles; uint16_t *p_sample; int b_stereo; - + p_buffer = p_adec->p_block; b_stereo = p_adec->p_wf->nChannels == 2 ? 1 : 0; @@ -576,28 +670,28 @@ static void DecodeAdpcmImaWav( adec_thread_t *p_adec, CLAMP( channel[1].i_step_index, 0, 88 ); p_buffer++; } - + p_sample = (int16_t*)p_aout_buffer->p_buffer; if( b_stereo ) { - for( i_nibbles = 2 * (p_adec->i_block - 8); - i_nibbles > 0; + for( i_nibbles = 2 * (p_adec->i_block - 8); + i_nibbles > 0; i_nibbles -= 16 ) { int i; for( i = 0; i < 4; i++ ) { - p_sample[i * 4] = + p_sample[i * 4] = AdpcmImaWavExpandNibble(&channel[0],p_buffer[i]&0x0f); p_sample[i * 4 + 2] = AdpcmImaWavExpandNibble(&channel[0],p_buffer[i] >> 4); } p_buffer += 4; - + for( i = 0; i < 4; i++ ) { - p_sample[i * 4 + 1] = + p_sample[i * 4 + 1] = AdpcmImaWavExpandNibble(&channel[1],p_buffer[i]&0x0f); p_sample[i * 4 + 3] = AdpcmImaWavExpandNibble(&channel[1],p_buffer[i] >> 4); @@ -611,8 +705,8 @@ static void DecodeAdpcmImaWav( adec_thread_t *p_adec, } else { - for( i_nibbles = 2 * (p_adec->i_block - 4); - i_nibbles > 0; + for( i_nibbles = 2 * (p_adec->i_block - 4); + i_nibbles > 0; i_nibbles -= 2, p_buffer++ ) { *p_sample =AdpcmImaWavExpandNibble( &channel[0], (*p_buffer)&0x0f ); @@ -623,6 +717,168 @@ static void DecodeAdpcmImaWav( adec_thread_t *p_adec, } } +/* + * Ima4 in QT file + */ +static void DecodeAdpcmImaQT( adec_thread_t *p_adec, + aout_buffer_t *p_aout_buffer ) +{ + uint8_t *p_buffer; + adpcm_ima_wav_channel_t channel[2]; + int i_nibbles; + uint16_t *p_sample; + int i_ch; + int i_step; + + p_buffer = p_adec->p_block; + i_step = p_adec->p_wf->nChannels; + + for( i_ch = 0; i_ch < p_adec->p_wf->nChannels; i_ch++ ) + { + p_sample = ((int16_t*)p_aout_buffer->p_buffer) + i_ch; + /* load preambule */ + channel[i_ch].i_predictor = (int16_t)((( ( p_buffer[0] << 1 )|( p_buffer[1] >> 7 ) ))<<7); + channel[i_ch].i_step_index = p_buffer[1]&0x7f; + + CLAMP( channel[i_ch].i_step_index, 0, 88 ); + p_buffer += 2; + + for( i_nibbles = 0; i_nibbles < 64; i_nibbles +=2 ) + { + *p_sample = AdpcmImaWavExpandNibble( &channel[i_ch], (*p_buffer)&0x0f); + p_sample += i_step; + + *p_sample = AdpcmImaWavExpandNibble( &channel[i_ch], (*p_buffer >> 4)&0x0f); + p_sample += i_step; + + p_buffer++; + } + } +} + +/* + * Dk4 + */ + +static void DecodeAdpcmDk4( adec_thread_t *p_adec, + aout_buffer_t *p_aout_buffer) +{ + uint8_t *p_buffer; + adpcm_ima_wav_channel_t channel[2]; + int i_nibbles; + uint16_t *p_sample; + int b_stereo; + + p_buffer = p_adec->p_block; + b_stereo = p_adec->p_wf->nChannels == 2 ? 1 : 0; + + GetWord( channel[0].i_predictor ); + GetByte( channel[0].i_step_index ); + CLAMP( channel[0].i_step_index, 0, 88 ); + p_buffer++; + + if( b_stereo ) + { + GetWord( channel[1].i_predictor ); + GetByte( channel[1].i_step_index ); + CLAMP( channel[1].i_step_index, 0, 88 ); + p_buffer++; + } + + p_sample = (int16_t*)p_aout_buffer->p_buffer; + + /* first output predictor */ + *p_sample++ = channel[0].i_predictor; + if( b_stereo ) + { + *p_sample++ = channel[1].i_predictor; + } + + for( i_nibbles = 0; + i_nibbles < p_adec->i_block - 4 * (b_stereo ? 2:1 ); + i_nibbles++ ) + { + *p_sample++ = AdpcmImaWavExpandNibble( &channel[0], + (*p_buffer) >> 4); + *p_sample++ = AdpcmImaWavExpandNibble( &channel[b_stereo ? 1 : 0], + (*p_buffer)&0x0f); + + p_buffer++; + } +} + +/* + * Dk3 + */ + +static void DecodeAdpcmDk3( adec_thread_t *p_adec, + aout_buffer_t *p_aout_buffer) +{ + uint8_t *p_buffer, *p_end; + adpcm_ima_wav_channel_t sum; + adpcm_ima_wav_channel_t diff; + uint16_t *p_sample; + int i_diff_value; + + p_buffer = p_adec->p_block; + p_end = p_buffer + p_adec->i_block; + p_buffer += 10; + GetWord( sum.i_predictor ); + GetWord( diff.i_predictor ); + GetByte( sum.i_step_index ); + GetByte( diff.i_step_index ); + + p_sample = (int16_t*)p_aout_buffer->p_buffer; + i_diff_value = diff.i_predictor; + /* we process 6 nibbles at once */ + //for( i_group = 0; i_group < ( p_adec->i_block -16 ) / 3; i_group++ ) + while( p_buffer + 1 <= p_end ) + { + /* first 3 nibbles */ + AdpcmImaWavExpandNibble( &sum, + (*p_buffer)&0x0f); + + AdpcmImaWavExpandNibble( &diff, + (*p_buffer) >> 4 ); + + i_diff_value = ( i_diff_value + diff.i_predictor ) / 2; + + *p_sample++ = sum.i_predictor + i_diff_value; + *p_sample++ = sum.i_predictor - i_diff_value; + + p_buffer++; + + AdpcmImaWavExpandNibble( &sum, + (*p_buffer)&0x0f); + + *p_sample++ = sum.i_predictor + i_diff_value; + *p_sample++ = sum.i_predictor - i_diff_value; + + /* now last 3 nibbles */ + AdpcmImaWavExpandNibble( &sum, + (*p_buffer)>>4); + p_buffer++; + if( p_buffer < p_end ) + { + AdpcmImaWavExpandNibble( &diff, + (*p_buffer)&0x0f ); + + i_diff_value = ( i_diff_value + diff.i_predictor ) / 2; + + *p_sample++ = sum.i_predictor + i_diff_value; + *p_sample++ = sum.i_predictor - i_diff_value; + + AdpcmImaWavExpandNibble( &sum, + (*p_buffer)>>4); + p_buffer++; + + *p_sample++ = sum.i_predictor + i_diff_value; + *p_sample++ = sum.i_predictor - i_diff_value; + } + + } + +}