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libavcodec/8svx.c

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00001 /*
00002  * 8SVX audio decoder
00003  * Copyright (C) 2008 Jaikrishnan Menon
00004  *
00005  * This file is part of Libav.
00006  *
00007  * Libav is free software; you can redistribute it and/or
00008  * modify it under the terms of the GNU Lesser General Public
00009  * License as published by the Free Software Foundation; either
00010  * version 2.1 of the License, or (at your option) any later version.
00011  *
00012  * Libav is distributed in the hope that it will be useful,
00013  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00014  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00015  * Lesser General Public License for more details.
00016  *
00017  * You should have received a copy of the GNU Lesser General Public
00018  * License along with Libav; if not, write to the Free Software
00019  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
00020  */
00021 
00031 #include "avcodec.h"
00032 
00034 typedef struct EightSvxContext {
00035     AVFrame frame;
00036     uint8_t fib_acc[2];
00037     const int8_t *table;
00038 
00039     /* buffer used to store the whole first packet.
00040        data is only sent as one large packet */
00041     uint8_t *data[2];
00042     int data_size;
00043     int data_idx;
00044 } EightSvxContext;
00045 
00046 static const int8_t fibonacci[16]   = { -34, -21, -13,  -8, -5, -3, -2, -1,
00047                                           0,   1,   2,   3,  5,  8, 13, 21 };
00048 static const int8_t exponential[16] = { -128, -64, -32, -16, -8, -4, -2, -1,
00049                                            0,   1,   2,   4,  8, 16, 32, 64 };
00050 
00051 #define MAX_FRAME_SIZE 32768
00052 
00059 static void delta_decode(uint8_t *dst, const uint8_t *src, int src_size,
00060                          uint8_t *state, const int8_t *table, int channels)
00061 {
00062     uint8_t val = *state;
00063 
00064     while (src_size--) {
00065         uint8_t d = *src++;
00066         val = av_clip_uint8(val + table[d & 0xF]);
00067         *dst = val;
00068         dst += channels;
00069         val = av_clip_uint8(val + table[d >> 4]);
00070         *dst = val;
00071         dst += channels;
00072     }
00073 
00074     *state = val;
00075 }
00076 
00077 static void raw_decode(uint8_t *dst, const int8_t *src, int src_size,
00078                        int channels)
00079 {
00080     while (src_size--) {
00081         *dst = *src++ + 128;
00082         dst += channels;
00083     }
00084 }
00085 
00087 static int eightsvx_decode_frame(AVCodecContext *avctx, void *data,
00088                                  int *got_frame_ptr, AVPacket *avpkt)
00089 {
00090     EightSvxContext *esc = avctx->priv_data;
00091     int buf_size;
00092     uint8_t *out_data;
00093     int ret;
00094     int is_compr = (avctx->codec_id != CODEC_ID_PCM_S8_PLANAR);
00095 
00096     /* for the first packet, copy data to buffer */
00097     if (avpkt->data) {
00098         int hdr_size  = is_compr ? 2 : 0;
00099         int chan_size = (avpkt->size - hdr_size * avctx->channels) / avctx->channels;
00100 
00101         if (avpkt->size < hdr_size * avctx->channels) {
00102             av_log(avctx, AV_LOG_ERROR, "packet size is too small\n");
00103             return AVERROR(EINVAL);
00104         }
00105         if (esc->data[0]) {
00106             av_log(avctx, AV_LOG_ERROR, "unexpected data after first packet\n");
00107             return AVERROR(EINVAL);
00108         }
00109 
00110         if (is_compr) {
00111         esc->fib_acc[0] = avpkt->data[1] + 128;
00112         if (avctx->channels == 2)
00113             esc->fib_acc[1] = avpkt->data[2+chan_size+1] + 128;
00114         }
00115 
00116         esc->data_idx  = 0;
00117         esc->data_size = chan_size;
00118         if (!(esc->data[0] = av_malloc(chan_size)))
00119             return AVERROR(ENOMEM);
00120         if (avctx->channels == 2) {
00121             if (!(esc->data[1] = av_malloc(chan_size))) {
00122                 av_freep(&esc->data[0]);
00123                 return AVERROR(ENOMEM);
00124             }
00125         }
00126         memcpy(esc->data[0], &avpkt->data[hdr_size], chan_size);
00127         if (avctx->channels == 2)
00128             memcpy(esc->data[1], &avpkt->data[2*hdr_size+chan_size], chan_size);
00129     }
00130     if (!esc->data[0]) {
00131         av_log(avctx, AV_LOG_ERROR, "unexpected empty packet\n");
00132         return AVERROR(EINVAL);
00133     }
00134 
00135     /* decode next piece of data from the buffer */
00136     buf_size = FFMIN(MAX_FRAME_SIZE, esc->data_size - esc->data_idx);
00137     if (buf_size <= 0) {
00138         *got_frame_ptr = 0;
00139         return avpkt->size;
00140     }
00141 
00142     /* get output buffer */
00143     esc->frame.nb_samples = buf_size * (is_compr + 1);
00144     if ((ret = avctx->get_buffer(avctx, &esc->frame)) < 0) {
00145         av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
00146         return ret;
00147     }
00148     out_data = esc->frame.data[0];
00149 
00150     if (is_compr) {
00151     delta_decode(out_data, &esc->data[0][esc->data_idx], buf_size,
00152                  &esc->fib_acc[0], esc->table, avctx->channels);
00153     if (avctx->channels == 2) {
00154         delta_decode(&out_data[1], &esc->data[1][esc->data_idx], buf_size,
00155                     &esc->fib_acc[1], esc->table, avctx->channels);
00156     }
00157     } else {
00158         int ch;
00159         for (ch = 0; ch < avctx->channels; ch++) {
00160             raw_decode((int8_t *)&out_data[ch], &esc->data[ch][esc->data_idx],
00161                        buf_size, avctx->channels);
00162         }
00163     }
00164     esc->data_idx += buf_size;
00165 
00166     *got_frame_ptr   = 1;
00167     *(AVFrame *)data = esc->frame;
00168 
00169     return avpkt->size;
00170 }
00171 
00173 static av_cold int eightsvx_decode_init(AVCodecContext *avctx)
00174 {
00175     EightSvxContext *esc = avctx->priv_data;
00176 
00177     if (avctx->channels < 1 || avctx->channels > 2) {
00178         av_log(avctx, AV_LOG_ERROR, "8SVX does not support more than 2 channels\n");
00179         return AVERROR(EINVAL);
00180     }
00181 
00182     switch(avctx->codec->id) {
00183         case CODEC_ID_8SVX_FIB:
00184           esc->table = fibonacci;
00185           break;
00186         case CODEC_ID_8SVX_EXP:
00187           esc->table = exponential;
00188           break;
00189         case CODEC_ID_PCM_S8_PLANAR:
00190             break;
00191         default:
00192           return -1;
00193     }
00194     avctx->sample_fmt = AV_SAMPLE_FMT_U8;
00195 
00196     avcodec_get_frame_defaults(&esc->frame);
00197     avctx->coded_frame = &esc->frame;
00198 
00199     return 0;
00200 }
00201 
00202 static av_cold int eightsvx_decode_close(AVCodecContext *avctx)
00203 {
00204     EightSvxContext *esc = avctx->priv_data;
00205 
00206     av_freep(&esc->data[0]);
00207     av_freep(&esc->data[1]);
00208 
00209     return 0;
00210 }
00211 
00212 AVCodec ff_eightsvx_fib_decoder = {
00213   .name           = "8svx_fib",
00214   .type           = AVMEDIA_TYPE_AUDIO,
00215   .id             = CODEC_ID_8SVX_FIB,
00216   .priv_data_size = sizeof (EightSvxContext),
00217   .init           = eightsvx_decode_init,
00218   .close          = eightsvx_decode_close,
00219   .decode         = eightsvx_decode_frame,
00220   .capabilities   = CODEC_CAP_DELAY | CODEC_CAP_DR1,
00221   .long_name      = NULL_IF_CONFIG_SMALL("8SVX fibonacci"),
00222 };
00223 
00224 AVCodec ff_eightsvx_exp_decoder = {
00225   .name           = "8svx_exp",
00226   .type           = AVMEDIA_TYPE_AUDIO,
00227   .id             = CODEC_ID_8SVX_EXP,
00228   .priv_data_size = sizeof (EightSvxContext),
00229   .init           = eightsvx_decode_init,
00230   .close          = eightsvx_decode_close,
00231   .decode         = eightsvx_decode_frame,
00232   .capabilities   = CODEC_CAP_DELAY | CODEC_CAP_DR1,
00233   .long_name      = NULL_IF_CONFIG_SMALL("8SVX exponential"),
00234 };
00235 
00236 AVCodec ff_pcm_s8_planar_decoder = {
00237     .name           = "pcm_s8_planar",
00238     .type           = AVMEDIA_TYPE_AUDIO,
00239     .id             = CODEC_ID_PCM_S8_PLANAR,
00240     .priv_data_size = sizeof(EightSvxContext),
00241     .init           = eightsvx_decode_init,
00242     .close          = eightsvx_decode_close,
00243     .decode         = eightsvx_decode_frame,
00244     .capabilities   = CODEC_CAP_DELAY | CODEC_CAP_DR1,
00245     .long_name      = NULL_IF_CONFIG_SMALL("PCM signed 8-bit planar"),
00246 };
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