vgmstream/src/coding/ea_decoder.c

#include "coding.h"
#include "../util.h"

/* Various EA ADPCM codecs */

static const int32_t EA_XA_TABLE[28] = {
    0,0,240,0,
    460,-208,0x0188,-220,
    0x0000,0x0000,0x00F0,0x0000,
    0x01CC,0x0000,0x0188,0x0000,
    0x0000,0x0000,0x0000,0x0000,
    -208,-1,-220,-1,
    0x0000,0x0000,0x0000,0x3F70
};

static const int32_t EA_TABLE[20]= {
    0x00000000, 0x000000F0, 0x000001CC, 0x00000188,
    0x00000000, 0x00000000, 0xFFFFFF30, 0xFFFFFF24,
    0x00000000, 0x00000001, 0x00000003, 0x00000004,
    0x00000007, 0x00000008, 0x0000000A, 0x0000000B,
    0x00000000, 0xFFFFFFFF, 0xFFFFFFFD, 0xFFFFFFFC
};

/* EA EAXA, evolved from CDXA */
void decode_ea_xa(VGMSTREAMCHANNEL * stream, sample * outbuf, int channelspacing, int32_t first_sample, int32_t samples_to_do,int channel) {
    uint8_t frame_info;
    int32_t sample_count;
    int32_t coef1,coef2;
    int i,shift;
    off_t channel_offset = stream->channel_start_offset; //suboffset within channel

    first_sample = first_sample%28;

    /* header */
    frame_info = (uint8_t)read_8bit(stream->offset+channel_offset,stream->streamfile);
    channel_offset++;

    if (frame_info == 0xEE) { /* PCM frame (used in later revisions), always BE */
        stream->adpcm_history1_32 = read_16bitBE(stream->offset+channel_offset+0x00,stream->streamfile);
        stream->adpcm_history2_32 = read_16bitBE(stream->offset+channel_offset+0x02,stream->streamfile);
        channel_offset += 4;

        for (i=first_sample,sample_count=0; i<first_sample+samples_to_do; i++,sample_count+=channelspacing) {
            outbuf[sample_count] = read_16bitBE(stream->offset+channel_offset,stream->streamfile);
            channel_offset+=2;
        }

        // Only increment offset on complete frame
        if (channel_offset-stream->channel_start_offset == (2*28)+5)
            stream->channel_start_offset += (2*28)+5;

    } else { /* ADPCM frame */
        coef1 = EA_XA_TABLE[(((frame_info >> 4) & 0x0F) << 1)];
        coef2 = EA_XA_TABLE[(((frame_info >> 4) & 0x0F) << 1) + 1];
        shift = (frame_info & 0x0F) + 8;

        for (i=first_sample,sample_count=0; i<first_sample+samples_to_do; i++,sample_count+=channelspacing) {
            uint8_t sample_byte = (uint8_t)read_8bit(stream->offset+channel_offset+i/2,stream->streamfile);
            int32_t sample = ((((i&1?
                            sample_byte & 0x0F:
                            sample_byte >> 4
                          ) << 0x1C) >> shift) +
                          (coef1 * stream->adpcm_history1_32) + (coef2 * stream->adpcm_history2_32)) >> 8;

            outbuf[sample_count] = clamp16(sample);
            stream->adpcm_history2_32 = stream->adpcm_history1_32;
            stream->adpcm_history1_32 = sample;
        }

        channel_offset+=i/2;

        // Only increment offset on complete frame
        if(channel_offset - stream->channel_start_offset == 0x0F)
            stream->channel_start_offset += 0x0F;
    }
}

/* EA MicroTalk 10:1 (aka "EA ADPCM") */
void decode_ea_mt10(VGMSTREAM * vgmstream, sample * outbuf, int channelspacing, int32_t first_sample, int32_t samples_to_do,int channel) {
    uint8_t frame_info;
    int32_t sample_count;
    int32_t coef1,coef2;
    int i, shift;
    VGMSTREAMCHANNEL *stream = &(vgmstream->ch[channel]);
    off_t channel_offset=stream->channel_start_offset;

    vgmstream->get_high_nibble = !vgmstream->get_high_nibble; /* for stereo subinterleave, L=high nibble, R=low nibble */

    first_sample = first_sample%28;

    /* header */ //todo mono/interleave decoder
    frame_info = read_8bit(stream->offset+channel_offset,stream->streamfile);
    channel_offset++;
	coef1 = EA_TABLE[(vgmstream->get_high_nibble ? frame_info & 0x0F: frame_info >> 4)];
	coef2 = EA_TABLE[(vgmstream->get_high_nibble ? frame_info & 0x0F: frame_info >> 4) + 4];

    frame_info = read_8bit(stream->offset+channel_offset,stream->streamfile);
    channel_offset++;
	shift = (vgmstream->get_high_nibble ? frame_info & 0x0F : frame_info >> 4) + 8;


    for (i=first_sample,sample_count=0; i<first_sample+samples_to_do; i++,sample_count+=channelspacing) {
        uint8_t sample_byte;
        int32_t sample;

        sample_byte = (uint8_t)read_8bit(stream->offset+channel_offset+i,stream->streamfile);

        sample = ((((vgmstream->get_high_nibble?
                        sample_byte & 0x0F:
                        sample_byte >> 4
                      ) << 0x1C) >> shift) +
                      (coef1 * stream->adpcm_history1_32) + (coef2 * stream->adpcm_history2_32) + 0x80) >> 8;

        outbuf[sample_count] = clamp16(sample);
        stream->adpcm_history2_32 = stream->adpcm_history1_32;
        stream->adpcm_history1_32 = sample;
    }
    channel_offset+=i;

    // Only increment offset on complete frame
    if(channel_offset-stream->channel_start_offset==0x1E)
        stream->channel_start_offset+=0x1E;
}


/* EA MicroTalk 5:1, unknown variation */
//void decode_ea_mt5(VGMSTREAM * vgmstream, sample * outbuf, int channelspacing, int32_t first_sample, int32_t samples_to_do,int channel)


/* Maxis EAXA, yet another CDXA variation */
void decode_maxis_adpcm(VGMSTREAM * vgmstream, sample * outbuf, int channelspacing, int32_t first_sample, int32_t samples_to_do,int channel) {
    uint8_t frame_info;
    int32_t sample_count;
    int32_t coef1,coef2;
    int i,shift;
    int frameSize = channelspacing*15;//mono samples have a frame of 15, stereo files have frames of 30
    VGMSTREAMCHANNEL *stream = &(vgmstream->ch[channel]);
    off_t channel_offset=stream->channel_start_offset;

    first_sample = first_sample%28;
    frame_info = read_8bit(channel_offset,stream->streamfile);

    coef1 = EA_TABLE[frame_info >> 4];
    coef2 = EA_TABLE[(frame_info >> 4) + 4];
    shift = (frame_info & 0x0F)+8;

    channel_offset+=channelspacing;
    //stream->offset = first_sample*channelspacing/2;

    for (i=first_sample,sample_count=0; i<first_sample+samples_to_do; i++,sample_count+=channelspacing) {
        uint8_t sample_byte;
        int32_t sample;

        sample_byte = (uint8_t)read_8bit(stream->offset+channel_offset,stream->streamfile);

        sample = (((((i&1)?
                        sample_byte & 0x0F:
                        sample_byte >> 4
                      ) << 0x1C) >> shift) +
                      (coef1 * stream->adpcm_history1_32) + (coef2 * stream->adpcm_history2_32) + 0x80) >> 8;

        outbuf[sample_count] = clamp16(sample);
        stream->adpcm_history2_32 = stream->adpcm_history1_32;
        stream->adpcm_history1_32 = sample;

        if(i&1)
            stream->offset+=channelspacing;
    }

    channel_offset+=i;

    // Only increment offset on complete frame

    if(channel_offset-stream->channel_start_offset==frameSize) {
        stream->channel_start_offset+=frameSize;
        stream->offset=0;
    }
}