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00037 #include "avcodec.h"
00038 #include "internal.h"
00039 #include "get_bits.h"
00040 #include "g722.h"
00041 #include "libavutil/opt.h"
00042
00043 #define OFFSET(x) offsetof(G722Context, x)
00044 #define AD AV_OPT_FLAG_AUDIO_PARAM | AV_OPT_FLAG_DECODING_PARAM
00045 static const AVOption options[] = {
00046 { "bits_per_codeword", "Bits per G722 codeword", OFFSET(bits_per_codeword), AV_OPT_TYPE_FLAGS, { 8 }, 6, 8, AD },
00047 { NULL }
00048 };
00049
00050 static const AVClass g722_decoder_class = {
00051 .class_name = "g722 decoder",
00052 .item_name = av_default_item_name,
00053 .option = options,
00054 .version = LIBAVUTIL_VERSION_INT,
00055 };
00056
00057 static av_cold int g722_decode_init(AVCodecContext * avctx)
00058 {
00059 G722Context *c = avctx->priv_data;
00060
00061 if (avctx->channels != 1) {
00062 av_log(avctx, AV_LOG_ERROR, "Only mono tracks are allowed.\n");
00063 return AVERROR_INVALIDDATA;
00064 }
00065 avctx->sample_fmt = AV_SAMPLE_FMT_S16;
00066
00067 c->band[0].scale_factor = 8;
00068 c->band[1].scale_factor = 2;
00069 c->prev_samples_pos = 22;
00070
00071 avcodec_get_frame_defaults(&c->frame);
00072 avctx->coded_frame = &c->frame;
00073
00074 return 0;
00075 }
00076
00077 static const int16_t low_inv_quant5[32] = {
00078 -35, -35, -2919, -2195, -1765, -1458, -1219, -1023,
00079 -858, -714, -587, -473, -370, -276, -190, -110,
00080 2919, 2195, 1765, 1458, 1219, 1023, 858, 714,
00081 587, 473, 370, 276, 190, 110, 35, -35
00082 };
00083
00084 static const int16_t *low_inv_quants[3] = { ff_g722_low_inv_quant6,
00085 low_inv_quant5,
00086 ff_g722_low_inv_quant4 };
00087
00088 static int g722_decode_frame(AVCodecContext *avctx, void *data,
00089 int *got_frame_ptr, AVPacket *avpkt)
00090 {
00091 G722Context *c = avctx->priv_data;
00092 int16_t *out_buf;
00093 int j, ret;
00094 const int skip = 8 - c->bits_per_codeword;
00095 const int16_t *quantizer_table = low_inv_quants[skip];
00096 GetBitContext gb;
00097
00098
00099 c->frame.nb_samples = avpkt->size * 2;
00100 if ((ret = ff_get_buffer(avctx, &c->frame)) < 0) {
00101 av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
00102 return ret;
00103 }
00104 out_buf = (int16_t *)c->frame.data[0];
00105
00106 init_get_bits(&gb, avpkt->data, avpkt->size * 8);
00107
00108 for (j = 0; j < avpkt->size; j++) {
00109 int ilow, ihigh, rlow, rhigh, dhigh;
00110 int xout1, xout2;
00111
00112 ihigh = get_bits(&gb, 2);
00113 ilow = get_bits(&gb, 6 - skip);
00114 skip_bits(&gb, skip);
00115
00116 rlow = av_clip((c->band[0].scale_factor * quantizer_table[ilow] >> 10)
00117 + c->band[0].s_predictor, -16384, 16383);
00118
00119 ff_g722_update_low_predictor(&c->band[0], ilow >> (2 - skip));
00120
00121 dhigh = c->band[1].scale_factor * ff_g722_high_inv_quant[ihigh] >> 10;
00122 rhigh = av_clip(dhigh + c->band[1].s_predictor, -16384, 16383);
00123
00124 ff_g722_update_high_predictor(&c->band[1], dhigh, ihigh);
00125
00126 c->prev_samples[c->prev_samples_pos++] = rlow + rhigh;
00127 c->prev_samples[c->prev_samples_pos++] = rlow - rhigh;
00128 ff_g722_apply_qmf(c->prev_samples + c->prev_samples_pos - 24,
00129 &xout1, &xout2);
00130 *out_buf++ = av_clip_int16(xout1 >> 11);
00131 *out_buf++ = av_clip_int16(xout2 >> 11);
00132 if (c->prev_samples_pos >= PREV_SAMPLES_BUF_SIZE) {
00133 memmove(c->prev_samples, c->prev_samples + c->prev_samples_pos - 22,
00134 22 * sizeof(c->prev_samples[0]));
00135 c->prev_samples_pos = 22;
00136 }
00137 }
00138
00139 *got_frame_ptr = 1;
00140 *(AVFrame *)data = c->frame;
00141
00142 return avpkt->size;
00143 }
00144
00145 AVCodec ff_adpcm_g722_decoder = {
00146 .name = "g722",
00147 .type = AVMEDIA_TYPE_AUDIO,
00148 .id = CODEC_ID_ADPCM_G722,
00149 .priv_data_size = sizeof(G722Context),
00150 .init = g722_decode_init,
00151 .decode = g722_decode_frame,
00152 .capabilities = CODEC_CAP_DR1,
00153 .long_name = NULL_IF_CONFIG_SMALL("G.722 ADPCM"),
00154 .priv_class = &g722_decoder_class,
00155 };