From 034eeaa17f2541663f12666008109c267620f4b2 Mon Sep 17 00:00:00 2001 From: Mike Melanson Date: Mon, 28 Mar 2005 18:05:25 +0000 Subject: Westwood SND1 decoder, courtesy of Kostya Originally committed as revision 4094 to svn://svn.ffmpeg.org/ffmpeg/trunk --- libavcodec/ws-snd1.c | 145 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 145 insertions(+) create mode 100644 libavcodec/ws-snd1.c (limited to 'libavcodec/ws-snd1.c') diff --git a/libavcodec/ws-snd1.c b/libavcodec/ws-snd1.c new file mode 100644 index 0000000000..5ac4c61bdc --- /dev/null +++ b/libavcodec/ws-snd1.c @@ -0,0 +1,145 @@ +/* + * Westwood SNDx codecs + * Copyright (c) 2005 Konstantin Shishkov + * + * This library is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public + * License as published by the Free Software Foundation; either + * version 2 of the License, or (at your option) any later version. + * + * This library is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with this library; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + */ +#include "avcodec.h" + +/** + * @file ws-snd.c + * Westwood SNDx codecs. + * + * Reference documents about VQA format and its audio codecs + * can be found here: + * http://www.multimedia.cx + */ + +typedef struct { +} WSSNDContext; + +static const char ws_adpcm_2bit[] = { -2, -1, 0, 1}; +static const char ws_adpcm_4bit[] = { + -9, -8, -6, -5, -4, -3, -2, -1, + 0, 1, 2, 3, 4, 5, 6, 8 }; + +#define CLIP8(a) if(a>127)a=127;if(a<-128)a=-128; + +static int ws_snd_decode_init(AVCodecContext * avctx) +{ +// WSSNDContext *c = avctx->priv_data; + + return 0; +} + +static int ws_snd_decode_frame(AVCodecContext *avctx, + void *data, int *data_size, + uint8_t *buf, int buf_size) +{ +// WSSNDContext *c = avctx->priv_data; + + int in_size, out_size; + int sample = 0; + int i; + short *samples = data; + + if (!buf_size) + return 0; + + out_size = LE_16(&buf[0]); + *data_size = out_size * 2; + in_size = LE_16(&buf[2]); + buf += 4; + + if (in_size == out_size) { + for (i = 0; i < out_size; i++) + *samples++ = (*buf++ - 0x80) << 8; + return buf_size; + } + + while (out_size > 0) { + int code; + uint8_t count; + code = (*buf) >> 6; + count = (*buf) & 0x3F; + buf++; + switch(code) { + case 0: /* ADPCM 2-bit */ + for (count++; count > 0; count--) { + code = *buf++; + sample += ws_adpcm_2bit[code & 0x3]; + CLIP8(sample); + *samples++ = sample << 8; + sample += ws_adpcm_2bit[(code >> 2) & 0x3]; + CLIP8(sample); + *samples++ = sample << 8; + sample += ws_adpcm_2bit[(code >> 4) & 0x3]; + CLIP8(sample); + *samples++ = sample << 8; + sample += ws_adpcm_2bit[(code >> 6) & 0x3]; + CLIP8(sample); + *samples++ = sample << 8; + out_size -= 4; + } + break; + case 1: /* ADPCM 4-bit */ + for (count++; count > 0; count--) { + code = *buf++; + sample += ws_adpcm_4bit[code & 0xF]; + CLIP8(sample); + *samples++ = sample << 8; + sample += ws_adpcm_4bit[code >> 4]; + CLIP8(sample); + *samples++ = sample << 8; + out_size -= 2; + } + break; + case 2: /* no compression */ + if (count & 0x20) { /* big delta */ + char t; + t = count; + t <<= 3; + sample += t >> 3; + *samples++ = sample << 8; + out_size--; + } else { /* copy */ + for (count++; count > 0; count--) { + *samples++ = (*buf++ - 0x80) << 8; + out_size--; + } + sample = buf[-1] - 0x80; + } + break; + default: /* run */ + for(count++; count > 0; count--) { + *samples++ = sample << 8; + out_size--; + } + } + } + + return buf_size; +} + +AVCodec ws_snd1_decoder = { + "ws_snd1", + CODEC_TYPE_AUDIO, + CODEC_ID_WESTWOOD_SND1, + sizeof(WSSNDContext), + ws_snd_decode_init, + NULL, + NULL, + ws_snd_decode_frame, +}; -- cgit v1.2.3