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00021 #include "avcodec.h"
00022 #include "adx.h"
00023
00033
00034
00035 static void adx_decode(short *out,const unsigned char *in,PREV *prev)
00036 {
00037 int scale = AV_RB16(in);
00038 int i;
00039 int s0,s1,s2,d;
00040
00041
00042
00043 in+=2;
00044 s1 = prev->s1;
00045 s2 = prev->s2;
00046 for(i=0;i<16;i++) {
00047 d = in[i];
00048
00049 d = ((signed char)d >> 4);
00050 s0 = (BASEVOL*d*scale + SCALE1*s1 - SCALE2*s2)>>14;
00051 s2 = s1;
00052 s1 = av_clip_int16(s0);
00053 *out++=s1;
00054
00055 d = in[i];
00056
00057 d = ((signed char)(d<<4) >> 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 prev->s1 = s1;
00064 prev->s2 = s2;
00065
00066 }
00067
00068 static void adx_decode_stereo(short *out,const unsigned char *in,PREV *prev)
00069 {
00070 short tmp[32*2];
00071 int i;
00072
00073 adx_decode(tmp ,in ,prev);
00074 adx_decode(tmp+32,in+18,prev+1);
00075 for(i=0;i<32;i++) {
00076 out[i*2] = tmp[i];
00077 out[i*2+1] = tmp[i+32];
00078 }
00079 }
00080
00081
00082 static int adx_decode_header(AVCodecContext *avctx,const unsigned char *buf,size_t bufsize)
00083 {
00084 int offset;
00085
00086 if (buf[0]!=0x80) return 0;
00087 offset = (AV_RB32(buf)^0x80000000)+4;
00088 if (bufsize<offset || memcmp(buf+offset-6,"(c)CRI",6)) return 0;
00089
00090 avctx->channels = buf[7];
00091 avctx->sample_rate = AV_RB32(buf+8);
00092 avctx->bit_rate = avctx->sample_rate*avctx->channels*18*8/32;
00093
00094 return offset;
00095 }
00096
00097 static int adx_decode_frame(AVCodecContext *avctx,
00098 void *data, int *data_size,
00099 const uint8_t *buf0, int buf_size)
00100 {
00101 ADXContext *c = avctx->priv_data;
00102 short *samples = data;
00103 const uint8_t *buf = buf0;
00104 int rest = buf_size;
00105
00106 if (!c->header_parsed) {
00107 int hdrsize = adx_decode_header(avctx,buf,rest);
00108 if (hdrsize==0) return -1;
00109 c->header_parsed = 1;
00110 buf += hdrsize;
00111 rest -= hdrsize;
00112 }
00113
00114
00115
00116 if(rest/18 > *data_size/64)
00117 rest = (*data_size/64) * 18;
00118
00119 if (c->in_temp) {
00120 int copysize = 18*avctx->channels - c->in_temp;
00121 memcpy(c->dec_temp+c->in_temp,buf,copysize);
00122 rest -= copysize;
00123 buf += copysize;
00124 if (avctx->channels==1) {
00125 adx_decode(samples,c->dec_temp,c->prev);
00126 samples += 32;
00127 } else {
00128 adx_decode_stereo(samples,c->dec_temp,c->prev);
00129 samples += 32*2;
00130 }
00131 }
00132
00133 if (avctx->channels==1) {
00134 while(rest>=18) {
00135 adx_decode(samples,buf,c->prev);
00136 rest-=18;
00137 buf+=18;
00138 samples+=32;
00139 }
00140 } else {
00141 while(rest>=18*2) {
00142 adx_decode_stereo(samples,buf,c->prev);
00143 rest-=18*2;
00144 buf+=18*2;
00145 samples+=32*2;
00146 }
00147 }
00148
00149 c->in_temp = rest;
00150 if (rest) {
00151 memcpy(c->dec_temp,buf,rest);
00152 buf+=rest;
00153 }
00154 *data_size = (uint8_t*)samples - (uint8_t*)data;
00155
00156 return buf-buf0;
00157 }
00158
00159 AVCodec adpcm_adx_decoder = {
00160 "adpcm_adx",
00161 CODEC_TYPE_AUDIO,
00162 CODEC_ID_ADPCM_ADX,
00163 sizeof(ADXContext),
00164 NULL,
00165 NULL,
00166 NULL,
00167 adx_decode_frame,
00168 };
00169