libavcodec/adxdec.c

   1 /*
   2  * ADX ADPCM codecs
   3  * Copyright (c) 2001,2003 BERO
   4  *
   5  * This file is part of Libav.
   6  *
   7  * Libav is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU Lesser General Public
   9  * License as published by the Free Software Foundation; either
  10  * version 2.1 of the License, or (at your option) any later version.
  11  *
  12  * Libav is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * Lesser General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Lesser General Public
  18  * License along with Libav; if not, write to the Free Software
  19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  20  */
  21
  22 #include "libavutil/intreadwrite.h"
  23 #include "avcodec.h"
  24 #include "adx.h"
  25 #include "get_bits.h"
  26 #include "internal.h"
  27
  28 /**
  29  * @file
  30  * SEGA CRI adx codecs.
  31  *
  32  * Reference documents:
  33  * http://ku-www.ss.titech.ac.jp/~yatsushi/adx.html
  34  * adx2wav & wav2adx http://www.geocities.co.jp/Playtown/2004/
  35  */
  36
  37 static av_cold int adx_decode_init(AVCodecContext *avctx)
  38 {
  39     ADXContext *c = avctx->priv_data;
  40     int ret, header_size;
  41
  42     if (avctx->extradata_size >= 24) {
  43         if ((ret = avpriv_adx_decode_header(avctx, avctx->extradata,
  44                                             avctx->extradata_size, &header_size,
  45                                             c->coeff)) < 0) {
  46             av_log(avctx, AV_LOG_ERROR, "error parsing ADX header\n");
  47             return AVERROR_INVALIDDATA;
  48         }
  49         c->channels      = avctx->channels;
  50         c->header_parsed = 1;
  51     }
  52
  53     avctx->sample_fmt = AV_SAMPLE_FMT_S16P;
  54
  55     avcodec_get_frame_defaults(&c->frame);
  56     avctx->coded_frame = &c->frame;
  57
  58     return 0;
  59 }
  60
  61 /**
  62  * Decode 32 samples from 18 bytes.
  63  *
  64  * A 16-bit scalar value is applied to 32 residuals, which then have a
  65  * 2nd-order LPC filter applied to it to form the output signal for a single
  66  * channel.
  67  */
  68 static int adx_decode(ADXContext *c, int16_t *out, int offset,
  69                       const uint8_t *in, int ch)
  70 {
  71     ADXChannelState *prev = &c->prev[ch];
  72     GetBitContext gb;
  73     int scale = AV_RB16(in);
  74     int i;
  75     int s0, s1, s2, d;
  76
  77     /* check if this is an EOF packet */
  78     if (scale & 0x8000)
  79         return -1;
  80
  81     init_get_bits(&gb, in + 2, (BLOCK_SIZE - 2) * 8);
  82     out += offset;
  83     s1 = prev->s1;
  84     s2 = prev->s2;
  85     for (i = 0; i < BLOCK_SAMPLES; i++) {
  86         d  = get_sbits(&gb, 4);
  87         s0 = ((d << COEFF_BITS) * scale + c->coeff[0] * s1 + c->coeff[1] * s2) >> COEFF_BITS;
  88         s2 = s1;
  89         s1 = av_clip_int16(s0);
  90         *out++ = s1;
  91     }
  92     prev->s1 = s1;
  93     prev->s2 = s2;
  94
  95     return 0;
  96 }
  97
  98 static int adx_decode_frame(AVCodecContext *avctx, void *data,
  99                             int *got_frame_ptr, AVPacket *avpkt)
 100 {
 101     int buf_size        = avpkt->size;
 102     ADXContext *c       = avctx->priv_data;
 103     int16_t **samples;
 104     int samples_offset;
 105     const uint8_t *buf  = avpkt->data;
 106     int num_blocks, ch, ret;
 107
 108     if (c->eof) {
 109         *got_frame_ptr = 0;
 110         return buf_size;
 111     }
 112
 113     if (!c->header_parsed && buf_size >= 2 && AV_RB16(buf) == 0x8000) {
 114         int header_size;
 115         if ((ret = avpriv_adx_decode_header(avctx, buf, buf_size, &header_size,
 116                                             c->coeff)) < 0) {
 117             av_log(avctx, AV_LOG_ERROR, "error parsing ADX header\n");
 118             return AVERROR_INVALIDDATA;
 119         }
 120         c->channels      = avctx->channels;
 121         c->header_parsed = 1;
 122         if (buf_size < header_size)
 123             return AVERROR_INVALIDDATA;
 124         buf      += header_size;
 125         buf_size -= header_size;
 126     }
 127     if (!c->header_parsed)
 128         return AVERROR_INVALIDDATA;
 129
 130     /* calculate number of blocks in the packet */
 131     num_blocks = buf_size / (BLOCK_SIZE * c->channels);
 132
 133     /* if the packet is not an even multiple of BLOCK_SIZE, check for an EOF
 134        packet */
 135     if (!num_blocks || buf_size % (BLOCK_SIZE * avctx->channels)) {
 136         if (buf_size >= 4 && (AV_RB16(buf) & 0x8000)) {
 137             c->eof = 1;
 138             *got_frame_ptr = 0;
 139             return avpkt->size;
 140         }
 141         return AVERROR_INVALIDDATA;
 142     }
 143
 144     /* get output buffer */
 145     c->frame.nb_samples = num_blocks * BLOCK_SAMPLES;
 146     if ((ret = ff_get_buffer(avctx, &c->frame)) < 0) {
 147         av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
 148         return ret;
 149     }
 150     samples = (int16_t **)c->frame.extended_data;
 151     samples_offset = 0;
 152
 153     while (num_blocks--) {
 154         for (ch = 0; ch < c->channels; ch++) {
 155             if (adx_decode(c, samples[ch], samples_offset, buf, ch)) {
 156                 c->eof = 1;
 157                 buf = avpkt->data + avpkt->size;
 158                 break;
 159             }
 160             buf_size -= BLOCK_SIZE;
 161             buf      += BLOCK_SIZE;
 162         }
 163         samples_offset += BLOCK_SAMPLES;
 164     }
 165
 166     *got_frame_ptr   = 1;
 167     *(AVFrame *)data = c->frame;
 168
 169     return buf - avpkt->data;
 170 }
 171
 172 static void adx_decode_flush(AVCodecContext *avctx)
 173 {
 174     ADXContext *c = avctx->priv_data;
 175     memset(c->prev, 0, sizeof(c->prev));
 176     c->eof = 0;
 177 }
 178
 179 AVCodec ff_adpcm_adx_decoder = {
 180     .name           = "adpcm_adx",
 181     .type           = AVMEDIA_TYPE_AUDIO,
 182     .id             = AV_CODEC_ID_ADPCM_ADX,
 183     .priv_data_size = sizeof(ADXContext),
 184     .init           = adx_decode_init,
 185     .decode         = adx_decode_frame,
 186     .flush          = adx_decode_flush,
 187     .capabilities   = CODEC_CAP_DR1,
 188     .long_name      = NULL_IF_CONFIG_SMALL("SEGA CRI ADX ADPCM"),
 189     .sample_fmts    = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_S16P,
 190                                                       AV_SAMPLE_FMT_NONE },
 191 };