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00027 #include "avcodec.h"
00028
00029 struct AVResampleContext;
00030
00031 struct ReSampleContext {
00032 struct AVResampleContext *resample_context;
00033 short *temp[2];
00034 int temp_len;
00035 float ratio;
00036
00037 int input_channels, output_channels, filter_channels;
00038 };
00039
00040
00041 static void stereo_to_mono(short *output, short *input, int n1)
00042 {
00043 short *p, *q;
00044 int n = n1;
00045
00046 p = input;
00047 q = output;
00048 while (n >= 4) {
00049 q[0] = (p[0] + p[1]) >> 1;
00050 q[1] = (p[2] + p[3]) >> 1;
00051 q[2] = (p[4] + p[5]) >> 1;
00052 q[3] = (p[6] + p[7]) >> 1;
00053 q += 4;
00054 p += 8;
00055 n -= 4;
00056 }
00057 while (n > 0) {
00058 q[0] = (p[0] + p[1]) >> 1;
00059 q++;
00060 p += 2;
00061 n--;
00062 }
00063 }
00064
00065
00066 static void mono_to_stereo(short *output, short *input, int n1)
00067 {
00068 short *p, *q;
00069 int n = n1;
00070 int v;
00071
00072 p = input;
00073 q = output;
00074 while (n >= 4) {
00075 v = p[0]; q[0] = v; q[1] = v;
00076 v = p[1]; q[2] = v; q[3] = v;
00077 v = p[2]; q[4] = v; q[5] = v;
00078 v = p[3]; q[6] = v; q[7] = v;
00079 q += 8;
00080 p += 4;
00081 n -= 4;
00082 }
00083 while (n > 0) {
00084 v = p[0]; q[0] = v; q[1] = v;
00085 q += 2;
00086 p += 1;
00087 n--;
00088 }
00089 }
00090
00091
00092 static void stereo_split(short *output1, short *output2, short *input, int n)
00093 {
00094 int i;
00095
00096 for(i=0;i<n;i++) {
00097 *output1++ = *input++;
00098 *output2++ = *input++;
00099 }
00100 }
00101
00102 static void stereo_mux(short *output, short *input1, short *input2, int n)
00103 {
00104 int i;
00105
00106 for(i=0;i<n;i++) {
00107 *output++ = *input1++;
00108 *output++ = *input2++;
00109 }
00110 }
00111
00112 static void ac3_5p1_mux(short *output, short *input1, short *input2, int n)
00113 {
00114 int i;
00115 short l,r;
00116
00117 for(i=0;i<n;i++) {
00118 l=*input1++;
00119 r=*input2++;
00120 *output++ = l;
00121 *output++ = (l/2)+(r/2);
00122 *output++ = r;
00123 *output++ = 0;
00124 *output++ = 0;
00125 *output++ = 0;
00126 }
00127 }
00128
00129 ReSampleContext *audio_resample_init(int output_channels, int input_channels,
00130 int output_rate, int input_rate)
00131 {
00132 ReSampleContext *s;
00133
00134 if ( input_channels > 2)
00135 {
00136 av_log(NULL, AV_LOG_ERROR, "Resampling with input channels greater than 2 unsupported.\n");
00137 return NULL;
00138 }
00139
00140 s = av_mallocz(sizeof(ReSampleContext));
00141 if (!s)
00142 {
00143 av_log(NULL, AV_LOG_ERROR, "Can't allocate memory for resample context.\n");
00144 return NULL;
00145 }
00146
00147 s->ratio = (float)output_rate / (float)input_rate;
00148
00149 s->input_channels = input_channels;
00150 s->output_channels = output_channels;
00151
00152 s->filter_channels = s->input_channels;
00153 if (s->output_channels < s->filter_channels)
00154 s->filter_channels = s->output_channels;
00155
00156
00157
00158
00159
00160
00161 if(s->filter_channels>2)
00162 s->filter_channels = 2;
00163
00164 #define TAPS 16
00165 s->resample_context= av_resample_init(output_rate, input_rate, TAPS, 10, 0, 0.8);
00166
00167 return s;
00168 }
00169
00170
00171
00172 int audio_resample(ReSampleContext *s, short *output, short *input, int nb_samples)
00173 {
00174 int i, nb_samples1;
00175 short *bufin[2];
00176 short *bufout[2];
00177 short *buftmp2[2], *buftmp3[2];
00178 int lenout;
00179
00180 if (s->input_channels == s->output_channels && s->ratio == 1.0 && 0) {
00181
00182 memcpy(output, input, nb_samples * s->input_channels * sizeof(short));
00183 return nb_samples;
00184 }
00185
00186
00187 for(i=0; i<s->filter_channels; i++){
00188 bufin[i]= av_malloc( (nb_samples + s->temp_len) * sizeof(short) );
00189 memcpy(bufin[i], s->temp[i], s->temp_len * sizeof(short));
00190 buftmp2[i] = bufin[i] + s->temp_len;
00191 }
00192
00193
00194 lenout= 4*nb_samples * s->ratio + 16;
00195 bufout[0]= av_malloc( lenout * sizeof(short) );
00196 bufout[1]= av_malloc( lenout * sizeof(short) );
00197
00198 if (s->input_channels == 2 &&
00199 s->output_channels == 1) {
00200 buftmp3[0] = output;
00201 stereo_to_mono(buftmp2[0], input, nb_samples);
00202 } else if (s->output_channels >= 2 && s->input_channels == 1) {
00203 buftmp3[0] = bufout[0];
00204 memcpy(buftmp2[0], input, nb_samples*sizeof(short));
00205 } else if (s->output_channels >= 2) {
00206 buftmp3[0] = bufout[0];
00207 buftmp3[1] = bufout[1];
00208 stereo_split(buftmp2[0], buftmp2[1], input, nb_samples);
00209 } else {
00210 buftmp3[0] = output;
00211 memcpy(buftmp2[0], input, nb_samples*sizeof(short));
00212 }
00213
00214 nb_samples += s->temp_len;
00215
00216
00217 nb_samples1 = 0;
00218 for(i=0;i<s->filter_channels;i++) {
00219 int consumed;
00220 int is_last= i+1 == s->filter_channels;
00221
00222 nb_samples1 = av_resample(s->resample_context, buftmp3[i], bufin[i], &consumed, nb_samples, lenout, is_last);
00223 s->temp_len= nb_samples - consumed;
00224 s->temp[i]= av_realloc(s->temp[i], s->temp_len*sizeof(short));
00225 memcpy(s->temp[i], bufin[i] + consumed, s->temp_len*sizeof(short));
00226 }
00227
00228 if (s->output_channels == 2 && s->input_channels == 1) {
00229 mono_to_stereo(output, buftmp3[0], nb_samples1);
00230 } else if (s->output_channels == 2) {
00231 stereo_mux(output, buftmp3[0], buftmp3[1], nb_samples1);
00232 } else if (s->output_channels == 6) {
00233 ac3_5p1_mux(output, buftmp3[0], buftmp3[1], nb_samples1);
00234 }
00235
00236 for(i=0; i<s->filter_channels; i++)
00237 av_free(bufin[i]);
00238
00239 av_free(bufout[0]);
00240 av_free(bufout[1]);
00241 return nb_samples1;
00242 }
00243
00244 void audio_resample_close(ReSampleContext *s)
00245 {
00246 av_resample_close(s->resample_context);
00247 av_freep(&s->temp[0]);
00248 av_freep(&s->temp[1]);
00249 av_free(s);
00250 }