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FFmpeg/libavcodec/vqcdec.c
Andreas Rheinhardt 36e7f9b339 avcodec/vqcdec: Avoid unnecessary VLC structure 
Everything besides VLC.table is basically write-only
and even VLC.table can be removed by accessing the
underlying table directly.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
2023-10-31 20:47:00 +01:00

441 lines
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/*
* ViewQuest VQC decoder
* Copyright (C) 2022 Peter Ross
*
* 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 "avcodec.h"
#include "get_bits.h"
#include "codec_internal.h"
#include "decode.h"
#include "libavutil/thread.h"
#define VECTOR_VLC_BITS 6
static const uint8_t vector_nbits[] = {
2, 4, 4, 4, 4, 2, 4, 4,
6, 6, 6, 6, 6, 6, 6, 6
};
enum {
SKIP_3 = 0x10,
SKIP_4,
SKIP_5,
SKIP_6,
STOP_RUN,
SIGNED_8BIT,
SIGNED_6BIT
};
/* vector symbols are signed, but returned unsigned by get_vlc2()
codebook indexes are cast as uint8_t in seed_codebook() to compensate */
static const int8_t vector_symbols[] = {
0, SKIP_3, SKIP_4, SKIP_5, SKIP_6, STOP_RUN, 1, -1,
2, 3, 4, SIGNED_8BIT, -2, -3, -4, SIGNED_6BIT
};
static VLCElem vector_vlc[1 << VECTOR_VLC_BITS];
static av_cold void vqc_init_static_data(void)
{
VLC_INIT_STATIC_TABLE_FROM_LENGTHS(vector_vlc, VECTOR_VLC_BITS,
FF_ARRAY_ELEMS(vector_nbits),
vector_nbits, 1,
vector_symbols, 1, 1,
0, 0);
}
typedef struct VqcContext {
AVFrame *frame;
uint8_t * vectors;
int16_t * coeff, *tmp1, *tmp2;
int16_t codebook[4][256];
} VqcContext;
static av_cold int vqc_decode_init(AVCodecContext * avctx)
{
static AVOnce init_static_once = AV_ONCE_INIT;
VqcContext *s = avctx->priv_data;
if (avctx->width & 15)
return AVERROR_PATCHWELCOME;
s->vectors = av_malloc((avctx->width * avctx->height * 3) / 2);
if (!s->vectors)
return AVERROR(ENOMEM);
s->coeff = av_malloc_array(2 * avctx->width, sizeof(s->coeff[0]));
if (!s->coeff)
return AVERROR(ENOMEM);
s->tmp1 = av_malloc_array(avctx->width / 2, sizeof(s->tmp1[0]));
if (!s->tmp1)
return AVERROR(ENOMEM);
s->tmp2 = av_malloc_array(avctx->width / 2, sizeof(s->tmp2[0]));
if (!s->tmp2)
return AVERROR(ENOMEM);
avctx->pix_fmt = AV_PIX_FMT_YUV420P;
s->frame = av_frame_alloc();
if (!s->frame)
return AVERROR(ENOMEM);
ff_thread_once(&init_static_once, vqc_init_static_data);
return 0;
}
static int seed_pow1(int x)
{
return x >= 1 && x <= 5 ? 1 << x : 0;
}
static int seed_pow2(int x)
{
return x >= 1 && x <= 4 ? 1 << x : 1;
}
static int bias(int x, int c)
{
if (x < 0)
return x - c;
else if (x > 0)
return x + c;
else
return 0;
}
static void seed_codebooks(VqcContext * s, const int * seed)
{
int book1 = -256 * seed[3];
int book2 = -128 * seed[4];
int book3 = -128 * seed[5];
int book4 = -128 * seed[6];
for (int i = -128; i < 128; i++) {
s->codebook[0][(uint8_t)i] = book1;
s->codebook[1][(uint8_t)i] = bias(book2, seed[0]);
s->codebook[2][(uint8_t)i] = bias(book3, seed[1]);
s->codebook[3][(uint8_t)i] = bias(book4, seed[2]);
book1 += 2 * seed[3];
book2 += seed[4];
book3 += seed[5];
book4 += seed[6];
}
}
static int decode_vectors(VqcContext * s, const uint8_t * buf, int size, int width, int height)
{
GetBitContext gb;
uint8_t * vectors = s->vectors;
uint8_t * vectors_end = s->vectors + (width * height * 3) / 2;
memset(vectors, 0, 3 * width * height / 2);
init_get_bits8(&gb, buf, size);
for (int i = 0; i < 3 * width * height / 2 / 32; i++) {
uint8_t * dst = vectors;
int symbol;
*dst++ = get_bits(&gb, 8);
*dst++ = get_bits(&gb, 8);
while (show_bits(&gb, 2) != 2) {
if (dst >= vectors_end - 1)
return 0;
if (get_bits_left(&gb) < 4)
return AVERROR_INVALIDDATA;
if (!show_bits(&gb, 4)) {
*dst++ = 0;
*dst++ = 0;
skip_bits(&gb, 4);
continue;
}
symbol = get_vlc2(&gb, vector_vlc, VECTOR_VLC_BITS, 1);
switch(symbol) {
case SKIP_3: dst += 3; break;
case SKIP_4: dst += 4; break;
case SKIP_5: dst += 5; break;
case SKIP_6: dst += 6; break;
case SIGNED_8BIT: *dst++ = get_sbits(&gb, 8); break;
case SIGNED_6BIT: *dst++ = get_sbits(&gb, 6); break;
default:
*dst++ = symbol;
}
}
skip_bits(&gb, 2);
vectors += 32;
}
return 0;
}
static void load_coeffs(VqcContext * s, const uint8_t * v, int width, int coeff_width)
{
int16_t * c0 = s->coeff;
int16_t * c1 = s->coeff + coeff_width;
int16_t * c0_125 = s->coeff + (coeff_width >> 3);
int16_t * c1_125 = s->coeff + coeff_width + (coeff_width >> 3);
int16_t * c0_25 = s->coeff + (coeff_width >> 2);
int16_t * c1_25 = s->coeff + coeff_width + (coeff_width >> 2);
int16_t * c0_5 = s->coeff + (coeff_width >> 1);
int16_t * c1_5 = s->coeff + coeff_width + (coeff_width >> 1);
for (int i = 0; i < width; i++) {
c0[0] = s->codebook[0][v[0]];
c0[1] = s->codebook[0][v[1]];
c0 += 2;
c1[0] = s->codebook[0][v[2]];
c1[1] = s->codebook[0][v[3]];
c1 += 2;
c0_125[0] = s->codebook[1][v[4]];
c0_125[1] = s->codebook[1][v[5]];
c0_125 += 2;
c1_125[0] = s->codebook[1][v[6]];
c1_125[1] = s->codebook[1][v[7]];
c1_125 += 2;
c0_25[0] = s->codebook[2][v[8]];
c0_25[1] = s->codebook[2][v[9]];
c0_25[2] = s->codebook[2][v[10]];
c0_25[3] = s->codebook[2][v[11]];
c0_25 += 4;
c1_25[0] = s->codebook[2][v[12]];
c1_25[1] = s->codebook[2][v[13]];
c1_25[2] = s->codebook[2][v[14]];
c1_25[3] = s->codebook[2][v[15]];
c1_25 += 4;
if (v[16] | v[17] | v[18] | v[19]) {
c0_5[0] = s->codebook[3][v[16]];
c0_5[1] = s->codebook[3][v[17]];
c0_5[2] = s->codebook[3][v[18]];
c0_5[3] = s->codebook[3][v[19]];
} else {
c0_5[0] = c0_5[1] = c0_5[2] = c0_5[3] = 0;
}
if (v[20] | v[21] | v[22] | v[23]) {
c0_5[4] = s->codebook[3][v[20]];
c0_5[5] = s->codebook[3][v[21]];
c0_5[6] = s->codebook[3][v[22]];
c0_5[7] = s->codebook[3][v[23]];
} else {
c0_5[4] = c0_5[5] = c0_5[6] = c0_5[7] = 0;
}
c0_5 += 8;
if (v[24] | v[25] | v[26] | v[27]) {
c1_5[0] = s->codebook[3][v[24]];
c1_5[1] = s->codebook[3][v[25]];
c1_5[2] = s->codebook[3][v[26]];
c1_5[3] = s->codebook[3][v[27]];
} else {
c1_5[0] = c1_5[1] = c1_5[2] = c1_5[3] = 0;
}
if (v[28] | v[29] | v[30] | v[31]) {
c1_5[4] = s->codebook[3][v[28]];
c1_5[5] = s->codebook[3][v[29]];
c1_5[6] = s->codebook[3][v[30]];
c1_5[7] = s->codebook[3][v[31]];
} else {
c1_5[4] = c1_5[5] = c1_5[6] = c1_5[7] = 0;
}
c1_5 += 8;
v += 32;
}
}
static void transform1(const int16_t * a, const int16_t * b, int16_t * dst, int width)
{
int s0 = a[0] + (b[0] >> 1);
for (int i = 0; i < width / 2 - 1; i++) {
dst[i * 2] = s0;
s0 = a[i + 1] + ((b[i] + b[i + 1]) >> 1);
dst[i * 2 + 1] = ((dst[i * 2] + s0) >> 1) - 2 * b[i];
}
dst[width - 2] = s0;
dst[width - 1] = a[width / 2 - 1] + ((b[width / 2 - 2] - 2 * b[width / 2 - 1]) >> 2) - b[width / 2 - 1];
}
static uint8_t clip(int x)
{
return x >= -128 ? x <= 127 ? x + 0x80 : 0x00 : 0xFF;
}
static void transform2(const int16_t * a, const int16_t * b, uint8_t * dst, int width)
{
int s0 = a[0] + (b[0] >> 1);
int tmp;
for (int i = 0; i < width / 2 - 1; i++) {
dst[i * 2] = av_clip_uint8(s0 + 0x80);
tmp = a[i + 1] + ((b[i] + b[i + 1]) >> 1);
dst[i * 2 + 1] = av_clip_uint8(((tmp + s0) >> 1) - 2 * b[i] + 0x80);
s0 = tmp;
}
dst[width - 2] = clip(s0);
dst[width - 1] = clip(a[width / 2 - 1] + ((b[width / 2 - 2] - 2 * b[width / 2 - 1]) >> 2) - b[width / 2 - 1]);
}
static void decode_strip(VqcContext * s, uint8_t * dst, int stride, int width)
{
const int16_t * coeff;
for (int i = 0; i < width; i++) {
int v0 = s->coeff[i];
int v1 = s->coeff[width + i];
s->coeff[i] = v0 - v1;
s->coeff[width + i] = v0 + v1;
}
coeff = s->coeff;
transform1(coeff, coeff + width / 8, s->tmp1, width / 4);
transform1(s->tmp1, coeff + width / 4, s->tmp2, width / 2);
transform2(s->tmp2, coeff + width / 2, dst, width);
coeff += width;
dst += stride;
transform1(coeff, coeff + width / 8, s->tmp1, width / 4);
transform1(s->tmp1, coeff + width / 4, s->tmp2, width / 2);
transform2(s->tmp2, coeff + width / 2, dst, width);
}
static void decode_frame(VqcContext * s, int width, int height)
{
uint8_t * vectors = s->vectors;
uint8_t * y = s->frame->data[0];
uint8_t * u = s->frame->data[1];
uint8_t * v = s->frame->data[2];
for (int j = 0; j < height / 4; j++) {
load_coeffs(s, vectors, width / 16, width);
decode_strip(s, y, s->frame->linesize[0], width);
vectors += 2 * width;
y += 2 * s->frame->linesize[0];
load_coeffs(s, vectors, width / 32, width / 2);
decode_strip(s, u, s->frame->linesize[1], width / 2);
vectors += width;
u += 2 * s->frame->linesize[1];
load_coeffs(s, vectors, width / 16, width);
decode_strip(s, y, s->frame->linesize[0], width);
vectors += 2 * width;
y += 2 * s->frame->linesize[0];
load_coeffs(s, vectors, width / 32, width / 2);
decode_strip(s, v, s->frame->linesize[2], width / 2);
vectors += width;
v += 2 * s->frame->linesize[2];
}
}
static int vqc_decode_frame(AVCodecContext *avctx, AVFrame * rframe,
int * got_frame, AVPacket * avpkt)
{
VqcContext *s = avctx->priv_data;
int ret;
const uint8_t * buf = avpkt->data;
int cache, seed[7], gamma, contrast;
if (avpkt->size < 7)
return AVERROR_INVALIDDATA;
if ((ret = ff_reget_buffer(avctx, s->frame, 0)) < 0)
return ret;
av_log(avctx, AV_LOG_DEBUG, "VQC%d format\n", (buf[2] & 1) + 1);
if (((buf[0] >> 1) & 7) != 5) {
avpriv_request_sample(avctx, "subversion != 5\n");
return AVERROR_PATCHWELCOME;
}
cache = AV_RL24(buf + 4);
seed[2] = seed_pow1((cache >> 1) & 7);
seed[1] = seed_pow1((cache >> 4) & 7);
seed[0] = seed_pow1((cache >> 7) & 7);
seed[6] = seed_pow2((cache >> 10) & 7);
seed[5] = seed_pow2((cache >> 13) & 7);
seed[4] = seed_pow2((cache >> 16) & 7);
seed[3] = seed_pow2((cache >> 19) & 7);
gamma = buf[0] >> 4;
contrast = AV_RL16(buf + 2) >> 1;
if (gamma || contrast)
avpriv_request_sample(avctx, "gamma=0x%x, contrast=0x%x\n", gamma, contrast);
seed_codebooks(s, seed);
ret = decode_vectors(s, buf + 7, avpkt->size - 7, avctx->width, avctx->height);
if (ret < 0)
return ret;
decode_frame(s, avctx->width, avctx->height);
if ((ret = av_frame_ref(rframe, s->frame)) < 0)
return ret;
*got_frame = 1;
return avpkt->size;
}
static av_cold int vqc_decode_end(AVCodecContext * avctx)
{
VqcContext *s = avctx->priv_data;
av_freep(&s->vectors);
av_freep(&s->coeff);
av_freep(&s->tmp1);
av_freep(&s->tmp2);
av_frame_free(&s->frame);
return 0;
}
const FFCodec ff_vqc_decoder = {
.p.name = "vqc",
CODEC_LONG_NAME("ViewQuest VQC"),
.p.type = AVMEDIA_TYPE_VIDEO,
.p.id = AV_CODEC_ID_VQC,
.priv_data_size = sizeof(VqcContext),
.init = vqc_decode_init,
.close = vqc_decode_end,
FF_CODEC_DECODE_CB(vqc_decode_frame),
.p.capabilities = AV_CODEC_CAP_DR1,
.caps_internal = FF_CODEC_CAP_INIT_CLEANUP,
};
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