cd335de53f
This decoder does not have the AV_CODEC_CAP_CHANNEL_CONF set, so that number of channels has to be set by the user before avcodec_open2(). Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
133 lines
3.6 KiB
C
133 lines
3.6 KiB
C
/*
|
|
* DFPWM decoder
|
|
* Copyright (c) 2022 Jack Bruienne
|
|
* Copyright (c) 2012, 2016 Ben "GreaseMonkey" Russell
|
|
*
|
|
* 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
|
|
*/
|
|
|
|
/**
|
|
* @file
|
|
* DFPWM1a decoder
|
|
*/
|
|
|
|
#include "libavutil/internal.h"
|
|
#include "avcodec.h"
|
|
#include "codec_id.h"
|
|
#include "codec_internal.h"
|
|
#include "decode.h"
|
|
|
|
typedef struct {
|
|
int fq, q, s, lt;
|
|
} DFPWMState;
|
|
|
|
// DFPWM codec from https://github.com/ChenThread/dfpwm/blob/master/1a/
|
|
// Licensed in the public domain
|
|
|
|
static void au_decompress(DFPWMState *state, int fs, int len,
|
|
uint8_t *outbuf, const uint8_t *inbuf)
|
|
{
|
|
unsigned d;
|
|
for (int i = 0; i < len; i++) {
|
|
// get bits
|
|
d = *(inbuf++);
|
|
for (int j = 0; j < 8; j++) {
|
|
int nq, lq, st, ns, ov;
|
|
// set target
|
|
int t = ((d&1) ? 127 : -128);
|
|
d >>= 1;
|
|
|
|
// adjust charge
|
|
nq = state->q + ((state->s * (t-state->q) + 512)>>10);
|
|
if(nq == state->q && nq != t)
|
|
nq += (t == 127 ? 1 : -1);
|
|
lq = state->q;
|
|
state->q = nq;
|
|
|
|
// adjust strength
|
|
st = (t != state->lt ? 0 : 1023);
|
|
ns = state->s;
|
|
if(ns != st)
|
|
ns += (st != 0 ? 1 : -1);
|
|
if(ns < 8) ns = 8;
|
|
state->s = ns;
|
|
|
|
// FILTER: perform antijerk
|
|
ov = (t != state->lt ? (nq+lq+1)>>1 : nq);
|
|
|
|
// FILTER: perform LPF
|
|
state->fq += ((fs*(ov-state->fq) + 0x80)>>8);
|
|
ov = state->fq;
|
|
|
|
// output sample
|
|
*(outbuf++) = ov + 128;
|
|
|
|
state->lt = t;
|
|
}
|
|
}
|
|
}
|
|
|
|
static av_cold int dfpwm_dec_init(struct AVCodecContext *ctx)
|
|
{
|
|
DFPWMState *state = ctx->priv_data;
|
|
|
|
state->fq = 0;
|
|
state->q = 0;
|
|
state->s = 0;
|
|
state->lt = -128;
|
|
|
|
ctx->sample_fmt = AV_SAMPLE_FMT_U8;
|
|
ctx->bits_per_raw_sample = 8;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int dfpwm_dec_frame(struct AVCodecContext *ctx, AVFrame *frame,
|
|
int *got_frame, struct AVPacket *packet)
|
|
{
|
|
DFPWMState *state = ctx->priv_data;
|
|
int ret;
|
|
|
|
if (packet->size * 8LL % ctx->ch_layout.nb_channels)
|
|
return AVERROR_PATCHWELCOME;
|
|
|
|
frame->nb_samples = packet->size * 8LL / ctx->ch_layout.nb_channels;
|
|
if (frame->nb_samples <= 0) {
|
|
av_log(ctx, AV_LOG_ERROR, "invalid number of samples in packet\n");
|
|
return AVERROR_INVALIDDATA;
|
|
}
|
|
|
|
if ((ret = ff_get_buffer(ctx, frame, 0)) < 0)
|
|
return ret;
|
|
|
|
au_decompress(state, 140, packet->size, frame->data[0], packet->data);
|
|
|
|
*got_frame = 1;
|
|
return packet->size;
|
|
}
|
|
|
|
const FFCodec ff_dfpwm_decoder = {
|
|
.p.name = "dfpwm",
|
|
CODEC_LONG_NAME("DFPWM1a audio"),
|
|
.p.type = AVMEDIA_TYPE_AUDIO,
|
|
.p.id = AV_CODEC_ID_DFPWM,
|
|
.priv_data_size = sizeof(DFPWMState),
|
|
.init = dfpwm_dec_init,
|
|
FF_CODEC_DECODE_CB(dfpwm_dec_frame),
|
|
.p.capabilities = AV_CODEC_CAP_DR1,
|
|
};
|