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FFmpeg/libavcodec/mpc8.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

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/*
* Musepack SV8 decoder
* Copyright (c) 2007 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
*/
/**
* @file
* MPEG Audio Layer 1/2 -like codec with frames of 1152 samples
* divided into 32 subbands.
*/
#include "libavutil/channel_layout.h"
#include "libavutil/lfg.h"
#include "libavutil/thread.h"
#include "avcodec.h"
#include "get_bits.h"
#include "internal.h"
#include "mpegaudiodsp.h"
#include "mpc.h"
#include "mpc8data.h"
#include "mpc8huff.h"
static VLC band_vlc, scfi_vlc[2], dscf_vlc[2], res_vlc[2];
static VLC q1_vlc, q2_vlc[2], q3_vlc[2], quant_vlc[4][2], q9up_vlc;
static inline int mpc8_dec_base(GetBitContext *gb, int k, int n)
{
int len = mpc8_cnk_len[k-1][n-1] - 1;
int code = len ? get_bits_long(gb, len) : 0;
if (code >= mpc8_cnk_lost[k-1][n-1])
code = ((code << 1) | get_bits1(gb)) - mpc8_cnk_lost[k-1][n-1];
return code;
}
static inline int mpc8_dec_enum(GetBitContext *gb, int k, int n)
{
int bits = 0;
const uint32_t * C = mpc8_cnk[k-1];
int code = mpc8_dec_base(gb, k, n);
do {
n--;
if (code >= C[n]) {
bits |= 1U << n;
code -= C[n];
C -= 32;
k--;
}
} while(k > 0);
return bits;
}
static inline int mpc8_get_mod_golomb(GetBitContext *gb, int m)
{
if(mpc8_cnk_len[0][m] < 1) return 0;
return mpc8_dec_base(gb, 1, m+1);
}
static int mpc8_get_mask(GetBitContext *gb, int size, int t)
{
int mask = 0;
if(t && t != size)
mask = mpc8_dec_enum(gb, FFMIN(t, size - t), size);
if((t << 1) > size) mask = ~mask;
return mask;
}
static av_cold void build_vlc(VLC *vlc, unsigned *buf_offset,
const uint8_t codes_counts[16],
const uint8_t **syms, int offset)
{
static VLC_TYPE vlc_buf[9296][2];
uint8_t len[MPC8_MAX_VLC_SIZE];
unsigned num = 0;
vlc->table = &vlc_buf[*buf_offset];
vlc->table_allocated = FF_ARRAY_ELEMS(vlc_buf) - *buf_offset;
for (int i = 16; i > 0; i--)
for (unsigned tmp = num + codes_counts[i - 1]; num < tmp; num++)
len[num] = i;
ff_init_vlc_from_lengths(vlc, FFMIN(len[0], 9), num, len, 1,
*syms, 1, 1, offset, INIT_VLC_STATIC_OVERLONG, NULL);
*buf_offset += vlc->table_size;
*syms += num;
}
static av_cold void mpc8_init_static(void)
{
const uint8_t *q_syms = mpc8_q_syms, *bands_syms = mpc8_bands_syms;
const uint8_t *res_syms = mpc8_res_syms, *scfi_syms = mpc8_scfi_syms;
const uint8_t *dscf_syms = mpc8_dscf_syms;
unsigned offset = 0;
build_vlc(&band_vlc, &offset, mpc8_bands_len_counts, &bands_syms, 0);
build_vlc(&q1_vlc, &offset, mpc8_q1_len_counts, &q_syms, 0);
build_vlc(&q9up_vlc, &offset, mpc8_q9up_len_counts, &q_syms, 0);
for (int i = 0; i < 2; i++){
build_vlc(&scfi_vlc[i], &offset, mpc8_scfi_len_counts[i], &scfi_syms, 0);
build_vlc(&dscf_vlc[i], &offset, mpc8_dscf_len_counts[i], &dscf_syms, 0);
build_vlc(&res_vlc[i], &offset, mpc8_res_len_counts[i], &res_syms, 0);
build_vlc(&q2_vlc[i], &offset, mpc8_q2_len_counts[i], &q_syms, 0);
build_vlc(&q3_vlc[i], &offset, mpc8_q34_len_counts[i],
&q_syms, -48 - 16 * i);
for (int j = 0; j < 4; j++)
build_vlc(&quant_vlc[j][i], &offset, mpc8_q5_8_len_counts[i][j],
&q_syms, -((8 << j) - 1));
}
ff_mpa_synth_init_fixed();
}
static av_cold int mpc8_decode_init(AVCodecContext * avctx)
{
static AVOnce init_static_once = AV_ONCE_INIT;
MPCContext *c = avctx->priv_data;
GetBitContext gb;
int channels;
if(avctx->extradata_size < 2){
av_log(avctx, AV_LOG_ERROR, "Too small extradata size (%i)!\n", avctx->extradata_size);
return -1;
}
memset(c->oldDSCF, 0, sizeof(c->oldDSCF));
av_lfg_init(&c->rnd, 0xDEADBEEF);
ff_mpadsp_init(&c->mpadsp);
init_get_bits(&gb, avctx->extradata, 16);
skip_bits(&gb, 3);//sample rate
c->maxbands = get_bits(&gb, 5) + 1;
if (c->maxbands >= BANDS) {
av_log(avctx,AV_LOG_ERROR, "maxbands %d too high\n", c->maxbands);
return AVERROR_INVALIDDATA;
}
channels = get_bits(&gb, 4) + 1;
if (channels > 2) {
avpriv_request_sample(avctx, "Multichannel MPC SV8");
return AVERROR_PATCHWELCOME;
}
c->MSS = get_bits1(&gb);
c->frames = 1 << (get_bits(&gb, 3) * 2);
avctx->sample_fmt = AV_SAMPLE_FMT_S16P;
avctx->channel_layout = (channels==2) ? AV_CH_LAYOUT_STEREO : AV_CH_LAYOUT_MONO;
avctx->channels = channels;
ff_thread_once(&init_static_once, mpc8_init_static);
return 0;
}
static int mpc8_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;
MPCContext *c = avctx->priv_data;
GetBitContext gb2, *gb = &gb2;
int i, j, k, ch, cnt, res, t;
Band *bands = c->bands;
int off;
int maxband, keyframe;
int last[2];
keyframe = c->cur_frame == 0;
if(keyframe){
memset(c->Q, 0, sizeof(c->Q));
c->last_bits_used = 0;
}
if ((res = init_get_bits8(gb, buf, buf_size)) < 0)
return res;
skip_bits(gb, c->last_bits_used & 7);
if(keyframe)
maxband = mpc8_get_mod_golomb(gb, c->maxbands + 1);
else{
maxband = c->last_max_band + get_vlc2(gb, band_vlc.table, MPC8_BANDS_BITS, 2);
if(maxband > 32) maxband -= 33;
}
if (get_bits_left(gb) < 0) {
*got_frame_ptr = 0;
return buf_size;
}
if(maxband > c->maxbands + 1) {
av_log(avctx, AV_LOG_ERROR, "maxband %d too large\n",maxband);
return AVERROR_INVALIDDATA;
}
c->last_max_band = maxband;
/* read subband indexes */
if(maxband){
last[0] = last[1] = 0;
for(i = maxband - 1; i >= 0; i--){
for(ch = 0; ch < 2; ch++){
last[ch] = get_vlc2(gb, res_vlc[last[ch] > 2].table, MPC8_RES_BITS, 2) + last[ch];
if(last[ch] > 15) last[ch] -= 17;
bands[i].res[ch] = last[ch];
}
}
if(c->MSS){
int mask;
cnt = 0;
for(i = 0; i < maxband; i++)
if(bands[i].res[0] || bands[i].res[1])
cnt++;
t = mpc8_get_mod_golomb(gb, cnt);
mask = mpc8_get_mask(gb, cnt, t);
for(i = maxband - 1; i >= 0; i--)
if(bands[i].res[0] || bands[i].res[1]){
bands[i].msf = mask & 1;
mask >>= 1;
}
}
}
for(i = maxband; i < c->maxbands; i++)
bands[i].res[0] = bands[i].res[1] = 0;
if(keyframe){
for(i = 0; i < 32; i++)
c->oldDSCF[0][i] = c->oldDSCF[1][i] = 1;
}
for(i = 0; i < maxband; i++){
if(bands[i].res[0] || bands[i].res[1]){
cnt = !!bands[i].res[0] + !!bands[i].res[1] - 1;
if(cnt >= 0){
t = get_vlc2(gb, scfi_vlc[cnt].table, scfi_vlc[cnt].bits, 1);
if(bands[i].res[0]) bands[i].scfi[0] = t >> (2 * cnt);
if(bands[i].res[1]) bands[i].scfi[1] = t & 3;
}
}
}
for(i = 0; i < maxband; i++){
for(ch = 0; ch < 2; ch++){
if(!bands[i].res[ch]) continue;
if(c->oldDSCF[ch][i]){
bands[i].scf_idx[ch][0] = get_bits(gb, 7) - 6;
c->oldDSCF[ch][i] = 0;
}else{
t = get_vlc2(gb, dscf_vlc[1].table, MPC8_DSCF1_BITS, 2);
if(t == 64)
t += get_bits(gb, 6);
bands[i].scf_idx[ch][0] = ((bands[i].scf_idx[ch][2] + t - 25) & 0x7F) - 6;
}
for(j = 0; j < 2; j++){
if((bands[i].scfi[ch] << j) & 2)
bands[i].scf_idx[ch][j + 1] = bands[i].scf_idx[ch][j];
else{
t = get_vlc2(gb, dscf_vlc[0].table, MPC8_DSCF0_BITS, 2);
if(t == 31)
t = 64 + get_bits(gb, 6);
bands[i].scf_idx[ch][j + 1] = ((bands[i].scf_idx[ch][j] + t - 25) & 0x7F) - 6;
}
}
}
}
for(i = 0, off = 0; i < maxband; i++, off += SAMPLES_PER_BAND){
for(ch = 0; ch < 2; ch++){
res = bands[i].res[ch];
switch(res){
case -1:
for(j = 0; j < SAMPLES_PER_BAND; j++)
c->Q[ch][off + j] = (av_lfg_get(&c->rnd) & 0x3FC) - 510;
break;
case 0:
break;
case 1:
for(j = 0; j < SAMPLES_PER_BAND; j += SAMPLES_PER_BAND / 2){
cnt = get_vlc2(gb, q1_vlc.table, MPC8_Q1_BITS, 2);
t = mpc8_get_mask(gb, 18, cnt);
for(k = 0; k < SAMPLES_PER_BAND / 2; k++)
c->Q[ch][off + j + k] = t & (1 << (SAMPLES_PER_BAND / 2 - k - 1))
? (get_bits1(gb) << 1) - 1 : 0;
}
break;
case 2:
cnt = 6;//2*mpc8_thres[res]
for(j = 0; j < SAMPLES_PER_BAND; j += 3){
t = get_vlc2(gb, q2_vlc[cnt > 3].table, MPC8_Q2_BITS, 2);
c->Q[ch][off + j + 0] = mpc8_idx50[t];
c->Q[ch][off + j + 1] = mpc8_idx51[t];
c->Q[ch][off + j + 2] = mpc8_idx52[t];
cnt = (cnt >> 1) + mpc8_huffq2[t];
}
break;
case 3:
case 4:
for(j = 0; j < SAMPLES_PER_BAND; j += 2){
t = get_vlc2(gb, q3_vlc[res - 3].table, MPC8_Q3_BITS, 2);
c->Q[ch][off + j + 1] = t >> 4;
c->Q[ch][off + j + 0] = sign_extend(t, 4);
}
break;
case 5:
case 6:
case 7:
case 8:
cnt = 2 * mpc8_thres[res];
for(j = 0; j < SAMPLES_PER_BAND; j++){
const VLC *vlc = &quant_vlc[res - 5][cnt > mpc8_thres[res]];
c->Q[ch][off + j] = get_vlc2(gb, vlc->table, vlc->bits, 2);
cnt = (cnt >> 1) + FFABS(c->Q[ch][off + j]);
}
break;
default:
for(j = 0; j < SAMPLES_PER_BAND; j++){
c->Q[ch][off + j] = get_vlc2(gb, q9up_vlc.table, MPC8_Q9UP_BITS, 2);
if(res != 9){
c->Q[ch][off + j] <<= res - 9;
c->Q[ch][off + j] |= get_bits(gb, res - 9);
}
c->Q[ch][off + j] -= (1 << (res - 2)) - 1;
}
}
}
}
frame->nb_samples = MPC_FRAME_SIZE;
if ((res = ff_get_buffer(avctx, frame, 0)) < 0)
return res;
ff_mpc_dequantize_and_synth(c, maxband - 1,
(int16_t **)frame->extended_data,
avctx->channels);
c->cur_frame++;
c->last_bits_used = get_bits_count(gb);
if(c->cur_frame >= c->frames)
c->cur_frame = 0;
if (get_bits_left(gb) < 0) {
av_log(avctx, AV_LOG_ERROR, "Overread %d\n", -get_bits_left(gb));
c->last_bits_used = buf_size << 3;
} else if (c->cur_frame == 0 && get_bits_left(gb) < 8) {// we have only padding left
c->last_bits_used = buf_size << 3;
}
*got_frame_ptr = 1;
return c->cur_frame ? c->last_bits_used >> 3 : buf_size;
}
static av_cold void mpc8_decode_flush(AVCodecContext *avctx)
{
MPCContext *c = avctx->priv_data;
c->cur_frame = 0;
}
const AVCodec ff_mpc8_decoder = {
.name = "mpc8",
.long_name = NULL_IF_CONFIG_SMALL("Musepack SV8"),
.type = AVMEDIA_TYPE_AUDIO,
.id = AV_CODEC_ID_MUSEPACK8,
.priv_data_size = sizeof(MPCContext),
.init = mpc8_decode_init,
.decode = mpc8_decode_frame,
.flush = mpc8_decode_flush,
.capabilities = AV_CODEC_CAP_DR1 | AV_CODEC_CAP_CHANNEL_CONF,
.sample_fmts = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_S16P,
AV_SAMPLE_FMT_NONE },
.caps_internal = FF_CODEC_CAP_INIT_THREADSAFE,
};
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