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00022 #include "libavutil/intreadwrite.h"
00023 #include "avcodec.h"
00024 #include "adx.h"
00025
00035 static av_cold int adx_decode_init(AVCodecContext *avctx)
00036 {
00037 avctx->sample_fmt = SAMPLE_FMT_S16;
00038 return 0;
00039 }
00040
00041
00042
00043 static void adx_decode(short *out,const unsigned char *in,PREV *prev)
00044 {
00045 int scale = AV_RB16(in);
00046 int i;
00047 int s0,s1,s2,d;
00048
00049
00050
00051 in+=2;
00052 s1 = prev->s1;
00053 s2 = prev->s2;
00054 for(i=0;i<16;i++) {
00055 d = in[i];
00056
00057 d = ((signed char)d >> 4);
00058 s0 = (BASEVOL*d*scale + SCALE1*s1 - SCALE2*s2)>>14;
00059 s2 = s1;
00060 s1 = av_clip_int16(s0);
00061 *out++=s1;
00062
00063 d = in[i];
00064
00065 d = ((signed char)(d<<4) >> 4);
00066 s0 = (BASEVOL*d*scale + SCALE1*s1 - SCALE2*s2)>>14;
00067 s2 = s1;
00068 s1 = av_clip_int16(s0);
00069 *out++=s1;
00070 }
00071 prev->s1 = s1;
00072 prev->s2 = s2;
00073
00074 }
00075
00076 static void adx_decode_stereo(short *out,const unsigned char *in,PREV *prev)
00077 {
00078 short tmp[32*2];
00079 int i;
00080
00081 adx_decode(tmp ,in ,prev);
00082 adx_decode(tmp+32,in+18,prev+1);
00083 for(i=0;i<32;i++) {
00084 out[i*2] = tmp[i];
00085 out[i*2+1] = tmp[i+32];
00086 }
00087 }
00088
00089
00090 static int adx_decode_header(AVCodecContext *avctx,const unsigned char *buf,size_t bufsize)
00091 {
00092 int offset;
00093
00094 if (buf[0]!=0x80) return 0;
00095 offset = (AV_RB32(buf)^0x80000000)+4;
00096 if (bufsize<offset || memcmp(buf+offset-6,"(c)CRI",6)) return 0;
00097
00098 avctx->channels = buf[7];
00099 avctx->sample_rate = AV_RB32(buf+8);
00100 avctx->bit_rate = avctx->sample_rate*avctx->channels*18*8/32;
00101
00102 return offset;
00103 }
00104
00105 static int adx_decode_frame(AVCodecContext *avctx,
00106 void *data, int *data_size,
00107 const uint8_t *buf0, int buf_size)
00108 {
00109 ADXContext *c = avctx->priv_data;
00110 short *samples = data;
00111 const uint8_t *buf = buf0;
00112 int rest = buf_size;
00113
00114 if (!c->header_parsed) {
00115 int hdrsize = adx_decode_header(avctx,buf,rest);
00116 if (hdrsize==0) return -1;
00117 c->header_parsed = 1;
00118 buf += hdrsize;
00119 rest -= hdrsize;
00120 }
00121
00122
00123
00124 if(rest/18 > *data_size/64)
00125 rest = (*data_size/64) * 18;
00126
00127 if (c->in_temp) {
00128 int copysize = 18*avctx->channels - c->in_temp;
00129 memcpy(c->dec_temp+c->in_temp,buf,copysize);
00130 rest -= copysize;
00131 buf += copysize;
00132 if (avctx->channels==1) {
00133 adx_decode(samples,c->dec_temp,c->prev);
00134 samples += 32;
00135 } else {
00136 adx_decode_stereo(samples,c->dec_temp,c->prev);
00137 samples += 32*2;
00138 }
00139 }
00140
00141 if (avctx->channels==1) {
00142 while(rest>=18) {
00143 adx_decode(samples,buf,c->prev);
00144 rest-=18;
00145 buf+=18;
00146 samples+=32;
00147 }
00148 } else {
00149 while(rest>=18*2) {
00150 adx_decode_stereo(samples,buf,c->prev);
00151 rest-=18*2;
00152 buf+=18*2;
00153 samples+=32*2;
00154 }
00155 }
00156
00157 c->in_temp = rest;
00158 if (rest) {
00159 memcpy(c->dec_temp,buf,rest);
00160 buf+=rest;
00161 }
00162 *data_size = (uint8_t*)samples - (uint8_t*)data;
00163
00164 return buf-buf0;
00165 }
00166
00167 AVCodec adpcm_adx_decoder = {
00168 "adpcm_adx",
00169 CODEC_TYPE_AUDIO,
00170 CODEC_ID_ADPCM_ADX,
00171 sizeof(ADXContext),
00172 adx_decode_init,
00173 NULL,
00174 NULL,
00175 adx_decode_frame,
00176 .long_name = NULL_IF_CONFIG_SMALL("SEGA CRI ADX ADPCM"),
00177 };
00178