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FFmpeg/libavcodec/mss4.c
Andreas Rheinhardt 4243da4ff4 avcodec/codec_internal: Use union for FFCodec decode/encode callbacks 
This is possible, because every given FFCodec has to implement
exactly one of these. Doing so decreases sizeof(FFCodec) and
therefore decreases the size of the binary.
Notice that in case of position-independent code the decrease
is in .data.rel.ro, so that this translates to decreased
memory consumption.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
2022-04-05 20:02:37 +02:00

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/*
* Microsoft Screen 4 (aka Microsoft Expression Encoder Screen) decoder
* Copyright (c) 2012 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
* Microsoft Screen 4 (aka Microsoft Titanium Screen 2,
* aka Microsoft Expression Encoder Screen) decoder
*/
#include "libavutil/thread.h"
#include "avcodec.h"
#include "bytestream.h"
#include "codec_internal.h"
#include "get_bits.h"
#include "internal.h"
#include "jpegtables.h"
#include "mss34dsp.h"
#include "unary.h"
#define HEADER_SIZE 8
enum FrameType {
INTRA_FRAME = 0,
INTER_FRAME,
SKIP_FRAME
};
enum BlockType {
SKIP_BLOCK = 0,
DCT_BLOCK,
IMAGE_BLOCK,
};
enum CachePos {
LEFT = 0,
TOP_LEFT,
TOP,
};
static const uint8_t mss4_dc_vlc_lens[2][16] = {
{ 0, 1, 5, 1, 1, 1, 1, 2, 0, 0, 0, 0, 0, 0, 0, 0 },
{ 0, 3, 1, 1, 1, 1, 1, 1, 1, 2, 0, 0, 0, 0, 0, 0 }
};
static const uint8_t vec_len_syms[2][4] = {
{ 4, 2, 3, 1 },
{ 4, 1, 2, 3 }
};
static const uint8_t mss4_vec_entry_vlc_lens[2][16] = {
{ 0, 2, 2, 3, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
{ 0, 1, 5, 1, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 }
};
static const uint8_t mss4_vec_entry_vlc_syms[2][9] = {
{ 0, 7, 6, 5, 8, 4, 3, 1, 2 },
{ 0, 2, 3, 4, 5, 6, 7, 1, 8 }
};
#define MAX_ENTRIES 162
typedef struct MSS4Context {
AVFrame *pic;
int block[64];
uint8_t imgbuf[3][16 * 16];
int quality;
uint16_t quant_mat[2][64];
int *prev_dc[3];
ptrdiff_t dc_stride[3];
int dc_cache[4][4];
int prev_vec[3][4];
} MSS4Context;
static VLC dc_vlc[2], ac_vlc[2];
static VLC vec_entry_vlc[2];
static av_cold void mss4_init_vlc(VLC *vlc, unsigned *offset,
const uint8_t *lens, const uint8_t *syms)
{
static VLC_TYPE vlc_buf[2146][2];
uint8_t bits[MAX_ENTRIES];
int i, j;
int idx = 0;
for (i = 0; i < 16; i++) {
for (j = 0; j < lens[i]; j++) {
bits[idx] = i + 1;
idx++;
}
}
vlc->table = &vlc_buf[*offset];
vlc->table_allocated = FF_ARRAY_ELEMS(vlc_buf) - *offset;
ff_init_vlc_from_lengths(vlc, FFMIN(bits[idx - 1], 9), idx,
bits, 1, syms, 1, 1,
0, INIT_VLC_STATIC_OVERLONG, NULL);
*offset += vlc->table_size;
}
static av_cold void mss4_init_vlcs(void)
{
for (unsigned i = 0, offset = 0; i < 2; i++) {
mss4_init_vlc(&dc_vlc[i], &offset, mss4_dc_vlc_lens[i], NULL);
mss4_init_vlc(&ac_vlc[i], &offset,
i ? ff_mjpeg_bits_ac_chrominance + 1
: ff_mjpeg_bits_ac_luminance + 1,
i ? ff_mjpeg_val_ac_chrominance
: ff_mjpeg_val_ac_luminance);
mss4_init_vlc(&vec_entry_vlc[i], &offset, mss4_vec_entry_vlc_lens[i],
mss4_vec_entry_vlc_syms[i]);
}
}
/* This function returns values in the range
* (-range + 1; -range/2] U [range/2; range - 1)
* i.e.
* nbits = 0 -> 0
* nbits = 1 -> -1, 1
* nbits = 2 -> -3, -2, 2, 3
*/
static av_always_inline int get_coeff_bits(GetBitContext *gb, int nbits)
{
int val;
if (!nbits)
return 0;
val = get_bits(gb, nbits);
if (val < (1 << (nbits - 1)))
val -= (1 << nbits) - 1;
return val;
}
static inline int get_coeff(GetBitContext *gb, VLC *vlc)
{
int val = get_vlc2(gb, vlc->table, vlc->bits, 2);
return get_coeff_bits(gb, val);
}
static int mss4_decode_dct(GetBitContext *gb, VLC *dc_vlc, VLC *ac_vlc,
int *block, int *dc_cache,
int bx, int by, uint16_t *quant_mat)
{
int skip, val, pos = 1, zz_pos, dc;
memset(block, 0, sizeof(*block) * 64);
dc = get_coeff(gb, dc_vlc);
// DC prediction is the same as in MSS3
if (by) {
if (bx) {
int l, tl, t;
l = dc_cache[LEFT];
tl = dc_cache[TOP_LEFT];
t = dc_cache[TOP];
if (FFABS(t - tl) <= FFABS(l - tl))
dc += l;
else
dc += t;
} else {
dc += dc_cache[TOP];
}
} else if (bx) {
dc += dc_cache[LEFT];
}
dc_cache[LEFT] = dc;
block[0] = dc * quant_mat[0];
while (pos < 64) {
val = get_vlc2(gb, ac_vlc->table, 9, 2);
if (!val)
return 0;
if (val == -1)
return -1;
if (val == 0xF0) {
pos += 16;
continue;
}
skip = val >> 4;
val = get_coeff_bits(gb, val & 0xF);
pos += skip;
if (pos >= 64)
return -1;
zz_pos = ff_zigzag_direct[pos];
block[zz_pos] = val * quant_mat[zz_pos];
pos++;
}
return pos == 64 ? 0 : -1;
}
static int mss4_decode_dct_block(MSS4Context *c, GetBitContext *gb,
uint8_t *dst[3], int mb_x, int mb_y)
{
int i, j, k, ret;
uint8_t *out = dst[0];
for (j = 0; j < 2; j++) {
for (i = 0; i < 2; i++) {
int xpos = mb_x * 2 + i;
c->dc_cache[j][TOP_LEFT] = c->dc_cache[j][TOP];
c->dc_cache[j][TOP] = c->prev_dc[0][mb_x * 2 + i];
ret = mss4_decode_dct(gb, &dc_vlc[0], &ac_vlc[0], c->block,
c->dc_cache[j],
xpos, mb_y * 2 + j, c->quant_mat[0]);
if (ret)
return ret;
c->prev_dc[0][mb_x * 2 + i] = c->dc_cache[j][LEFT];
ff_mss34_dct_put(out + xpos * 8, c->pic->linesize[0],
c->block);
}
out += 8 * c->pic->linesize[0];
}
for (i = 1; i < 3; i++) {
c->dc_cache[i + 1][TOP_LEFT] = c->dc_cache[i + 1][TOP];
c->dc_cache[i + 1][TOP] = c->prev_dc[i][mb_x];
ret = mss4_decode_dct(gb, &dc_vlc[1], &ac_vlc[1],
c->block, c->dc_cache[i + 1], mb_x, mb_y,
c->quant_mat[1]);
if (ret)
return ret;
c->prev_dc[i][mb_x] = c->dc_cache[i + 1][LEFT];
ff_mss34_dct_put(c->imgbuf[i], 8, c->block);
out = dst[i] + mb_x * 16;
// Since the DCT block is coded as YUV420 and the whole frame as YUV444,
// we need to scale chroma.
for (j = 0; j < 16; j++) {
for (k = 0; k < 8; k++)
AV_WN16A(out + k * 2, c->imgbuf[i][k + (j & ~1) * 4] * 0x101);
out += c->pic->linesize[i];
}
}
return 0;
}
static void read_vec_pos(GetBitContext *gb, int *vec_pos, int *sel_flag,
int *sel_len, int *prev)
{
int i, y_flag = 0;
for (i = 2; i >= 0; i--) {
if (!sel_flag[i]) {
vec_pos[i] = 0;
continue;
}
if ((!i && !y_flag) || get_bits1(gb)) {
if (sel_len[i] > 0) {
int pval = prev[i];
vec_pos[i] = get_bits(gb, sel_len[i]);
if (vec_pos[i] >= pval)
vec_pos[i]++;
} else {
vec_pos[i] = !prev[i];
}
y_flag = 1;
} else {
vec_pos[i] = prev[i];
}
}
}
static int get_value_cached(GetBitContext *gb, int vec_pos, uint8_t *vec,
int vec_size, int component, int shift, int *prev)
{
if (vec_pos < vec_size)
return vec[vec_pos];
if (!get_bits1(gb))
return prev[component];
prev[component] = get_bits(gb, 8 - shift) << shift;
return prev[component];
}
#define MKVAL(vals) ((vals)[0] | ((vals)[1] << 3) | ((vals)[2] << 6))
/* Image mode - the hardest to comprehend MSS4 coding mode.
*
* In this mode all three 16x16 blocks are coded together with a method
* remotely similar to the methods employed in MSS1-MSS3.
* The idea is that every component has a vector of 1-4 most common symbols
* and an escape mode for reading new value from the bitstream. Decoding
* consists of retrieving pixel values from the vector or reading new ones
* from the bitstream; depending on flags read from the bitstream, these vector
* positions can be updated or reused from the state of the previous line
* or previous pixel.
*/
static int mss4_decode_image_block(MSS4Context *ctx, GetBitContext *gb,
uint8_t *picdst[3], int mb_x, int mb_y)
{
uint8_t vec[3][4];
int vec_len[3];
int sel_len[3], sel_flag[3];
int i, j, k, mode, split;
int prev_vec1 = 0, prev_split = 0;
int vals[3] = { 0 };
int prev_pix[3] = { 0 };
int prev_mode[16] = { 0 };
uint8_t *dst[3];
const int val_shift = ctx->quality == 100 ? 0 : 2;
for (i = 0; i < 3; i++)
dst[i] = ctx->imgbuf[i];
for (i = 0; i < 3; i++) {
vec_len[i] = vec_len_syms[!!i][get_unary(gb, 0, 3)];
for (j = 0; j < vec_len[i]; j++) {
vec[i][j] = get_coeff(gb, &vec_entry_vlc[!!i]);
vec[i][j] += ctx->prev_vec[i][j];
ctx->prev_vec[i][j] = vec[i][j];
}
sel_flag[i] = vec_len[i] > 1;
sel_len[i] = vec_len[i] > 2 ? vec_len[i] - 2 : 0;
}
for (j = 0; j < 16; j++) {
if (get_bits1(gb)) {
split = 0;
if (get_bits1(gb)) {
prev_mode[0] = 0;
vals[0] = vals[1] = vals[2] = 0;
mode = 2;
} else {
mode = get_bits1(gb);
if (mode)
split = get_bits(gb, 4);
}
for (i = 0; i < 16; i++) {
if (mode <= 1) {
vals[0] = prev_mode[i] & 7;
vals[1] = (prev_mode[i] >> 3) & 7;
vals[2] = prev_mode[i] >> 6;
if (mode == 1 && i == split) {
read_vec_pos(gb, vals, sel_flag, sel_len, vals);
}
} else if (mode == 2) {
if (get_bits1(gb))
read_vec_pos(gb, vals, sel_flag, sel_len, vals);
}
for (k = 0; k < 3; k++)
*dst[k]++ = get_value_cached(gb, vals[k], vec[k],
vec_len[k], k,
val_shift, prev_pix);
prev_mode[i] = MKVAL(vals);
}
} else {
if (get_bits1(gb)) {
split = get_bits(gb, 4);
if (split >= prev_split)
split++;
prev_split = split;
} else {
split = prev_split;
}
if (split) {
vals[0] = prev_mode[0] & 7;
vals[1] = (prev_mode[0] >> 3) & 7;
vals[2] = prev_mode[0] >> 6;
for (i = 0; i < 3; i++) {
for (k = 0; k < split; k++) {
*dst[i]++ = get_value_cached(gb, vals[i], vec[i],
vec_len[i], i, val_shift,
prev_pix);
prev_mode[k] = MKVAL(vals);
}
}
}
if (split != 16) {
vals[0] = prev_vec1 & 7;
vals[1] = (prev_vec1 >> 3) & 7;
vals[2] = prev_vec1 >> 6;
if (get_bits1(gb)) {
read_vec_pos(gb, vals, sel_flag, sel_len, vals);
prev_vec1 = MKVAL(vals);
}
for (i = 0; i < 3; i++) {
for (k = 0; k < 16 - split; k++) {
*dst[i]++ = get_value_cached(gb, vals[i], vec[i],
vec_len[i], i, val_shift,
prev_pix);
prev_mode[split + k] = MKVAL(vals);
}
}
}
}
}
for (i = 0; i < 3; i++)
for (j = 0; j < 16; j++)
memcpy(picdst[i] + mb_x * 16 + j * ctx->pic->linesize[i],
ctx->imgbuf[i] + j * 16, 16);
return 0;
}
static inline void mss4_update_dc_cache(MSS4Context *c, int mb_x)
{
int i;
c->dc_cache[0][TOP] = c->prev_dc[0][mb_x * 2 + 1];
c->dc_cache[0][LEFT] = 0;
c->dc_cache[1][TOP] = 0;
c->dc_cache[1][LEFT] = 0;
for (i = 0; i < 2; i++)
c->prev_dc[0][mb_x * 2 + i] = 0;
for (i = 1; i < 3; i++) {
c->dc_cache[i + 1][TOP] = c->prev_dc[i][mb_x];
c->dc_cache[i + 1][LEFT] = 0;
c->prev_dc[i][mb_x] = 0;
}
}
static int mss4_decode_frame(AVCodecContext *avctx, AVFrame *rframe,
int *got_frame, AVPacket *avpkt)
{
const uint8_t *buf = avpkt->data;
int buf_size = avpkt->size;
MSS4Context *c = avctx->priv_data;
GetBitContext gb;
GetByteContext bc;
uint8_t *dst[3];
int width, height, quality, frame_type;
int x, y, i, mb_width, mb_height, blk_type;
int ret;
if (buf_size < HEADER_SIZE) {
av_log(avctx, AV_LOG_ERROR,
"Frame should have at least %d bytes, got %d instead\n",
HEADER_SIZE, buf_size);
return AVERROR_INVALIDDATA;
}
bytestream2_init(&bc, buf, buf_size);
width = bytestream2_get_be16(&bc);
height = bytestream2_get_be16(&bc);
bytestream2_skip(&bc, 2);
quality = bytestream2_get_byte(&bc);
frame_type = bytestream2_get_byte(&bc);
if (width > avctx->width ||
height != avctx->height) {
av_log(avctx, AV_LOG_ERROR, "Invalid frame dimensions %dx%d\n",
width, height);
return AVERROR_INVALIDDATA;
}
if (quality < 1 || quality > 100) {
av_log(avctx, AV_LOG_ERROR, "Invalid quality setting %d\n", quality);
return AVERROR_INVALIDDATA;
}
if ((frame_type & ~3) || frame_type == 3) {
av_log(avctx, AV_LOG_ERROR, "Invalid frame type %d\n", frame_type);
return AVERROR_INVALIDDATA;
}
if (frame_type != SKIP_FRAME && !bytestream2_get_bytes_left(&bc)) {
av_log(avctx, AV_LOG_ERROR,
"Empty frame found but it is not a skip frame.\n");
return AVERROR_INVALIDDATA;
}
mb_width = FFALIGN(width, 16) >> 4;
mb_height = FFALIGN(height, 16) >> 4;
if (frame_type != SKIP_FRAME && 8*buf_size < 8*HEADER_SIZE + mb_width*mb_height)
return AVERROR_INVALIDDATA;
if ((ret = ff_reget_buffer(avctx, c->pic, 0)) < 0)
return ret;
c->pic->key_frame = (frame_type == INTRA_FRAME);
c->pic->pict_type = (frame_type == INTRA_FRAME) ? AV_PICTURE_TYPE_I
: AV_PICTURE_TYPE_P;
if (frame_type == SKIP_FRAME) {
*got_frame = 1;
if ((ret = av_frame_ref(rframe, c->pic)) < 0)
return ret;
return buf_size;
}
if (c->quality != quality) {
c->quality = quality;
for (i = 0; i < 2; i++)
ff_mss34_gen_quant_mat(c->quant_mat[i], quality, !i);
}
if ((ret = init_get_bits8(&gb, buf + HEADER_SIZE, buf_size - HEADER_SIZE)) < 0)
return ret;
dst[0] = c->pic->data[0];
dst[1] = c->pic->data[1];
dst[2] = c->pic->data[2];
memset(c->prev_vec, 0, sizeof(c->prev_vec));
for (y = 0; y < mb_height; y++) {
memset(c->dc_cache, 0, sizeof(c->dc_cache));
for (x = 0; x < mb_width; x++) {
blk_type = decode012(&gb);
switch (blk_type) {
case DCT_BLOCK:
if (mss4_decode_dct_block(c, &gb, dst, x, y) < 0) {
av_log(avctx, AV_LOG_ERROR,
"Error decoding DCT block %d,%d\n",
x, y);
return AVERROR_INVALIDDATA;
}
break;
case IMAGE_BLOCK:
if (mss4_decode_image_block(c, &gb, dst, x, y) < 0) {
av_log(avctx, AV_LOG_ERROR,
"Error decoding VQ block %d,%d\n",
x, y);
return AVERROR_INVALIDDATA;
}
break;
case SKIP_BLOCK:
if (frame_type == INTRA_FRAME) {
av_log(avctx, AV_LOG_ERROR, "Skip block in intra frame\n");
return AVERROR_INVALIDDATA;
}
break;
}
if (blk_type != DCT_BLOCK)
mss4_update_dc_cache(c, x);
}
dst[0] += c->pic->linesize[0] * 16;
dst[1] += c->pic->linesize[1] * 16;
dst[2] += c->pic->linesize[2] * 16;
}
if ((ret = av_frame_ref(rframe, c->pic)) < 0)
return ret;
*got_frame = 1;
return buf_size;
}
static av_cold int mss4_decode_end(AVCodecContext *avctx)
{
MSS4Context * const c = avctx->priv_data;
int i;
av_frame_free(&c->pic);
for (i = 0; i < 3; i++)
av_freep(&c->prev_dc[i]);
return 0;
}
static av_cold int mss4_decode_init(AVCodecContext *avctx)
{
static AVOnce init_static_once = AV_ONCE_INIT;
MSS4Context * const c = avctx->priv_data;
int i;
for (i = 0; i < 3; i++) {
c->dc_stride[i] = FFALIGN(avctx->width, 16) >> (2 + !!i);
c->prev_dc[i] = av_malloc_array(c->dc_stride[i], sizeof(**c->prev_dc));
if (!c->prev_dc[i]) {
av_log(avctx, AV_LOG_ERROR, "Cannot allocate buffer\n");
return AVERROR(ENOMEM);
}
}
c->pic = av_frame_alloc();
if (!c->pic)
return AVERROR(ENOMEM);
avctx->pix_fmt = AV_PIX_FMT_YUV444P;
ff_thread_once(&init_static_once, mss4_init_vlcs);
return 0;
}
const FFCodec ff_mts2_decoder = {
.p.name = "mts2",
.p.long_name = NULL_IF_CONFIG_SMALL("MS Expression Encoder Screen"),
.p.type = AVMEDIA_TYPE_VIDEO,
.p.id = AV_CODEC_ID_MTS2,
.priv_data_size = sizeof(MSS4Context),
.init = mss4_decode_init,
.close = mss4_decode_end,
FF_CODEC_DECODE_CB(mss4_decode_frame),
.p.capabilities = AV_CODEC_CAP_DR1,
.caps_internal = FF_CODEC_CAP_INIT_CLEANUP | FF_CODEC_CAP_INIT_THREADSAFE,
};
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