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00027 #include "avcodec.h"
00028 #include "mpegaudio.h"
00029 #include <lame/lame.h>
00030
00031 #define BUFFER_SIZE (7200 + MPA_FRAME_SIZE + MPA_FRAME_SIZE/4)
00032 typedef struct Mp3AudioContext {
00033 lame_global_flags *gfp;
00034 int stereo;
00035 uint8_t buffer[BUFFER_SIZE];
00036 int buffer_index;
00037 } Mp3AudioContext;
00038
00039 static int MP3lame_encode_init(AVCodecContext *avctx)
00040 {
00041 Mp3AudioContext *s = avctx->priv_data;
00042
00043 if (avctx->channels > 2)
00044 return -1;
00045
00046 s->stereo = avctx->channels > 1 ? 1 : 0;
00047
00048 if ((s->gfp = lame_init()) == NULL)
00049 goto err;
00050 lame_set_in_samplerate(s->gfp, avctx->sample_rate);
00051 lame_set_out_samplerate(s->gfp, avctx->sample_rate);
00052 lame_set_num_channels(s->gfp, avctx->channels);
00053
00054 lame_set_quality(s->gfp, 5);
00055
00056 lame_set_mode(s->gfp, JOINT_STEREO);
00057 lame_set_brate(s->gfp, avctx->bit_rate/1000);
00058 if(avctx->flags & CODEC_FLAG_QSCALE) {
00059 lame_set_brate(s->gfp, 0);
00060 lame_set_VBR(s->gfp, vbr_default);
00061 lame_set_VBR_q(s->gfp, avctx->global_quality / (float)FF_QP2LAMBDA);
00062 }
00063 lame_set_bWriteVbrTag(s->gfp,0);
00064 if (lame_init_params(s->gfp) < 0)
00065 goto err_close;
00066
00067 avctx->frame_size = lame_get_framesize(s->gfp);
00068
00069 avctx->coded_frame= avcodec_alloc_frame();
00070 avctx->coded_frame->key_frame= 1;
00071
00072 return 0;
00073
00074 err_close:
00075 lame_close(s->gfp);
00076 err:
00077 return -1;
00078 }
00079
00080 static const int sSampleRates[3] = {
00081 44100, 48000, 32000
00082 };
00083
00084 static const int sBitRates[2][3][15] = {
00085 { { 0, 32, 64, 96,128,160,192,224,256,288,320,352,384,416,448},
00086 { 0, 32, 48, 56, 64, 80, 96,112,128,160,192,224,256,320,384},
00087 { 0, 32, 40, 48, 56, 64, 80, 96,112,128,160,192,224,256,320}
00088 },
00089 { { 0, 32, 48, 56, 64, 80, 96,112,128,144,160,176,192,224,256},
00090 { 0, 8, 16, 24, 32, 40, 48, 56, 64, 80, 96,112,128,144,160},
00091 { 0, 8, 16, 24, 32, 40, 48, 56, 64, 80, 96,112,128,144,160}
00092 },
00093 };
00094
00095 static const int sSamplesPerFrame[2][3] =
00096 {
00097 { 384, 1152, 1152 },
00098 { 384, 1152, 576 }
00099 };
00100
00101 static const int sBitsPerSlot[3] = {
00102 32,
00103 8,
00104 8
00105 };
00106
00107 static int mp3len(void *data, int *samplesPerFrame, int *sampleRate)
00108 {
00109 uint32_t header = AV_RB32(data);
00110 int layerID = 3 - ((header >> 17) & 0x03);
00111 int bitRateID = ((header >> 12) & 0x0f);
00112 int sampleRateID = ((header >> 10) & 0x03);
00113 int bitsPerSlot = sBitsPerSlot[layerID];
00114 int isPadded = ((header >> 9) & 0x01);
00115 static int const mode_tab[4]= {2,3,1,0};
00116 int mode= mode_tab[(header >> 19) & 0x03];
00117 int mpeg_id= mode>0;
00118 int temp0, temp1, bitRate;
00119
00120 if ( (( header >> 21 ) & 0x7ff) != 0x7ff || mode == 3 || layerID==3 || sampleRateID==3) {
00121 return -1;
00122 }
00123
00124 if(!samplesPerFrame) samplesPerFrame= &temp0;
00125 if(!sampleRate ) sampleRate = &temp1;
00126
00127
00128
00129 *sampleRate = sSampleRates[sampleRateID]>>mode;
00130 bitRate = sBitRates[mpeg_id][layerID][bitRateID] * 1000;
00131 *samplesPerFrame = sSamplesPerFrame[mpeg_id][layerID];
00132
00133
00134 return *samplesPerFrame * bitRate / (bitsPerSlot * *sampleRate) + isPadded;
00135 }
00136
00137 static int MP3lame_encode_frame(AVCodecContext *avctx,
00138 unsigned char *frame, int buf_size, void *data)
00139 {
00140 Mp3AudioContext *s = avctx->priv_data;
00141 int len;
00142 int lame_result;
00143
00144
00145
00146 if(data){
00147 if (s->stereo) {
00148 lame_result = lame_encode_buffer_interleaved(
00149 s->gfp,
00150 data,
00151 avctx->frame_size,
00152 s->buffer + s->buffer_index,
00153 BUFFER_SIZE - s->buffer_index
00154 );
00155 } else {
00156 lame_result = lame_encode_buffer(
00157 s->gfp,
00158 data,
00159 data,
00160 avctx->frame_size,
00161 s->buffer + s->buffer_index,
00162 BUFFER_SIZE - s->buffer_index
00163 );
00164 }
00165 }else{
00166 lame_result= lame_encode_flush(
00167 s->gfp,
00168 s->buffer + s->buffer_index,
00169 BUFFER_SIZE - s->buffer_index
00170 );
00171 }
00172
00173 if(lame_result==-1) {
00174
00175 av_log(avctx, AV_LOG_ERROR, "lame: output buffer too small (buffer index: %d, free bytes: %d)\n", s->buffer_index, BUFFER_SIZE - s->buffer_index);
00176 return 0;
00177 }
00178
00179 s->buffer_index += lame_result;
00180
00181 if(s->buffer_index<4)
00182 return 0;
00183
00184 len= mp3len(s->buffer, NULL, NULL);
00185
00186 if(len <= s->buffer_index){
00187 memcpy(frame, s->buffer, len);
00188 s->buffer_index -= len;
00189
00190 memmove(s->buffer, s->buffer+len, s->buffer_index);
00191
00192
00193
00194
00195 return len;
00196 }else
00197 return 0;
00198 }
00199
00200 static int MP3lame_encode_close(AVCodecContext *avctx)
00201 {
00202 Mp3AudioContext *s = avctx->priv_data;
00203
00204 av_freep(&avctx->coded_frame);
00205
00206 lame_close(s->gfp);
00207 return 0;
00208 }
00209
00210
00211 AVCodec libmp3lame_encoder = {
00212 "libmp3lame",
00213 CODEC_TYPE_AUDIO,
00214 CODEC_ID_MP3,
00215 sizeof(Mp3AudioContext),
00216 MP3lame_encode_init,
00217 MP3lame_encode_frame,
00218 MP3lame_encode_close,
00219 .capabilities= CODEC_CAP_DELAY,
00220 };