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FFmpeg/libavcodec/ws-snd1.c
Andreas Rheinhardt a247ac640d avcodec: Constify AVCodecs
Given that the AVCodec.next pointer has now been removed, most of the
AVCodecs are not modified at all any more and can therefore be made
const (as this patch does); the only exceptions are the very few codecs
for external libraries that have a init_static_data callback.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
Signed-off-by: James Almer <jamrial@gmail.com>
2021-04-27 10:43:15 -03:00

183 lines
5.5 KiB
C

/*
* Westwood SNDx codecs
* Copyright (c) 2005 Konstantin Shishkov
*
* This file is part of FFmpeg.
*
* FFmpeg 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 2.1 of the License, or (at your option) any later version.
*
* FFmpeg 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 FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include <stdint.h>
#include "libavutil/channel_layout.h"
#include "libavutil/common.h"
#include "libavutil/intreadwrite.h"
#include "avcodec.h"
#include "internal.h"
/**
* @file
* Westwood SNDx codecs
*
* Reference documents about VQA format and its audio codecs
* can be found here:
* http://www.multimedia.cx
*/
static const int8_t ws_adpcm_4bit[] = {
-9, -8, -6, -5, -4, -3, -2, -1,
0, 1, 2, 3, 4, 5, 6, 8
};
static av_cold int ws_snd_decode_init(AVCodecContext *avctx)
{
avctx->channels = 1;
avctx->channel_layout = AV_CH_LAYOUT_MONO;
avctx->sample_fmt = AV_SAMPLE_FMT_U8;
return 0;
}
static int ws_snd_decode_frame(AVCodecContext *avctx, void *data,
int *got_frame_ptr, AVPacket *avpkt)
{
AVFrame *frame = data;
const uint8_t *buf = avpkt->data;
int buf_size = avpkt->size;
int in_size, out_size, ret;
int sample = 128;
uint8_t *samples;
uint8_t *samples_end;
if (!buf_size)
return 0;
if (buf_size < 4) {
av_log(avctx, AV_LOG_ERROR, "packet is too small\n");
return AVERROR(EINVAL);
}
out_size = AV_RL16(&buf[0]);
in_size = AV_RL16(&buf[2]);
buf += 4;
if (in_size > buf_size) {
av_log(avctx, AV_LOG_ERROR, "Frame data is larger than input buffer\n");
return AVERROR_INVALIDDATA;
}
/* get output buffer */
frame->nb_samples = out_size;
if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
return ret;
samples = frame->data[0];
samples_end = samples + out_size;
if (in_size == out_size) {
memcpy(samples, buf, out_size);
*got_frame_ptr = 1;
return buf_size;
}
while (samples < samples_end && buf - avpkt->data < buf_size) {
int code, smp, size;
uint8_t count;
code = *buf >> 6;
count = *buf & 0x3F;
buf++;
/* make sure we don't write past the output buffer */
switch (code) {
case 0: smp = 4 * (count + 1); break;
case 1: smp = 2 * (count + 1); break;
case 2: smp = (count & 0x20) ? 1 : count + 1; break;
default: smp = count + 1; break;
}
if (samples_end - samples < smp)
break;
/* make sure we don't read past the input buffer */
size = ((code == 2 && (count & 0x20)) || code == 3) ? 0 : count + 1;
if ((buf - avpkt->data) + size > buf_size)
break;
switch (code) {
case 0: /* ADPCM 2-bit */
for (count++; count > 0; count--) {
code = *buf++;
sample += ( code & 0x3) - 2;
sample = av_clip_uint8(sample);
*samples++ = sample;
sample += ((code >> 2) & 0x3) - 2;
sample = av_clip_uint8(sample);
*samples++ = sample;
sample += ((code >> 4) & 0x3) - 2;
sample = av_clip_uint8(sample);
*samples++ = sample;
sample += (code >> 6) - 2;
sample = av_clip_uint8(sample);
*samples++ = sample;
}
break;
case 1: /* ADPCM 4-bit */
for (count++; count > 0; count--) {
code = *buf++;
sample += ws_adpcm_4bit[code & 0xF];
sample = av_clip_uint8(sample);
*samples++ = sample;
sample += ws_adpcm_4bit[code >> 4];
sample = av_clip_uint8(sample);
*samples++ = sample;
}
break;
case 2: /* no compression */
if (count & 0x20) { /* big delta */
int8_t t;
t = count;
t <<= 3;
sample += t >> 3;
sample = av_clip_uint8(sample);
*samples++ = sample;
} else { /* copy */
memcpy(samples, buf, smp);
samples += smp;
buf += smp;
sample = buf[-1];
}
break;
default: /* run */
memset(samples, sample, smp);
samples += smp;
}
}
frame->nb_samples = samples - frame->data[0];
*got_frame_ptr = 1;
return buf_size;
}
const AVCodec ff_ws_snd1_decoder = {
.name = "ws_snd1",
.long_name = NULL_IF_CONFIG_SMALL("Westwood Audio (SND1)"),
.type = AVMEDIA_TYPE_AUDIO,
.id = AV_CODEC_ID_WESTWOOD_SND1,
.init = ws_snd_decode_init,
.decode = ws_snd_decode_frame,
.capabilities = AV_CODEC_CAP_DR1 | AV_CODEC_CAP_CHANNEL_CONF,
.caps_internal = FF_CODEC_CAP_INIT_THREADSAFE,
};