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mss1: move code that will be reused by MSS2 decoder into separate file

tags/n1.0
Kostya Shishkov 12 years ago
parent
49df339f4b
commit
0de4a563e4
4 changed files with 691 additions and 596 deletions
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  1. +1
    -1
      libavcodec/Makefile
  2. +26
    -595
      libavcodec/mss1.c
  3. +581
    -0
      libavcodec/mss12.c
  4. +83
    -0
      libavcodec/mss12.h

+ 1
- 1
libavcodec/Makefile View File

@@ -270,7 +270,7 @@ OBJS-$(CONFIG_MSMPEG4V3_ENCODER) += msmpeg4.o msmpeg4enc.o msmpeg4data.o \
mpeg4videodec.o
OBJS-$(CONFIG_MSRLE_DECODER) += msrle.o msrledec.o
OBJS-$(CONFIG_MSA1_DECODER) += mss3.o mss34dsp.o
OBJS-$(CONFIG_MSS1_DECODER) += mss1.o
OBJS-$(CONFIG_MSS1_DECODER) += mss1.o mss12.o
OBJS-$(CONFIG_MSVIDEO1_DECODER) += msvideo1.o
OBJS-$(CONFIG_MSZH_DECODER) += lcldec.o
OBJS-$(CONFIG_MTS2_DECODER) += mss4.o mss34dsp.o


+ 26
- 595
libavcodec/mss1.c View File

@@ -27,74 +27,13 @@
#include "libavutil/intfloat.h"
#include "libavutil/intreadwrite.h"
#include "avcodec.h"
#include "get_bits.h"

enum SplitMode {
SPLIT_VERT = 0,
SPLIT_HOR,
SPLIT_NONE
};

typedef struct ArithCoder {
int low, high, value;
GetBitContext *gb;
} ArithCoder;

#define MODEL_MIN_SYMS 2
#define MODEL_MAX_SYMS 256
#define THRESH_ADAPTIVE -1
#define THRESH_LOW 15
#define THRESH_HIGH 50

typedef struct Model {
int cum_prob[MODEL_MAX_SYMS + 1];
int weights[MODEL_MAX_SYMS + 1];
int idx2sym[MODEL_MAX_SYMS + 1];
int sym2idx[MODEL_MAX_SYMS + 1];
int num_syms;
int thr_weight, threshold;
} Model;

static const int sec_order_sizes[4] = { 1, 7, 6, 1 };

enum ContextDirection {
TOP_LEFT = 0,
TOP,
TOP_RIGHT,
LEFT
};

typedef struct PixContext {
int cache_size, num_syms;
uint8_t cache[12];
Model cache_model, full_model;
Model sec_models[4][8][4];
} PixContext;
#include "mss12.h"

typedef struct MSS1Context {
AVCodecContext *avctx;
MSS12Context ctx;
AVFrame pic;
uint8_t *pic_start;
int pic_stride;
uint8_t *mask;
int mask_linesize;
uint32_t pal[256];
int free_colours;
int keyframe;
Model intra_region, inter_region;
Model pivot, edge_mode, split_mode;
PixContext intra_pix_ctx, inter_pix_ctx;
int corrupted;
} MSS1Context;

static void arith_init(ArithCoder *c, GetBitContext *gb)
{
c->low = 0;
c->high = 0xFFFF;
c->value = get_bits(gb, 16);
c->gb = gb;
}

static void arith_normalise(ArithCoder *c)
{
for (;;) {
@@ -179,88 +118,6 @@ static int arith_get_prob(ArithCoder *c, int *probs)
return sym;
}

static int model_calc_threshold(Model *m)
{
int thr;

if (m->thr_weight == -1) {
thr = 2 * m->weights[m->num_syms] - 1;
thr = ((thr >> 1) + 4 * m->cum_prob[0]) / thr;
} else {
thr = m->num_syms * m->thr_weight;
}

return FFMIN(thr, 0x3FFF);
}

static void model_reset(Model *m)
{
int i;

for (i = 0; i <= m->num_syms; i++) {
m->weights[i] = 1;
m->cum_prob[i] = m->num_syms - i;
}
m->weights[0] = -1;
m->idx2sym[0] = -1;
m->sym2idx[m->num_syms] = -1;
for (i = 0; i < m->num_syms; i++) {
m->sym2idx[i] = i + 1;
m->idx2sym[i + 1] = i;
}
}

static av_cold void model_init(Model *m, int num_syms, int thr_weight)
{
m->num_syms = num_syms;
m->thr_weight = thr_weight;
m->threshold = model_calc_threshold(m);
model_reset(m);
}

static void model_rescale_weights(Model *m)
{
int i;
int cum_prob;

if (m->thr_weight == -1)
m->threshold = model_calc_threshold(m);
while (m->cum_prob[0] > m->threshold) {
cum_prob = 0;
for (i = m->num_syms; i >= 0; i--) {
m->cum_prob[i] = cum_prob;
m->weights[i] = (m->weights[i] + 1) >> 1;
cum_prob += m->weights[i];
}
}
}

static void model_update(Model *m, int val)
{
int i;

if (m->weights[val] == m->weights[val - 1]) {
for (i = val; m->weights[i - 1] == m->weights[val]; i--);
if (i != val) {
int sym1, sym2;

sym1 = m->idx2sym[val];
sym2 = m->idx2sym[i];

m->idx2sym[val] = sym2;
m->idx2sym[i] = sym1;
m->sym2idx[sym1] = i;
m->sym2idx[sym2] = val;

val = i;
}
}
m->weights[val]++;
for (i = val - 1; i >= 0; i--)
m->cum_prob[i]++;
model_rescale_weights(m);
}

static int arith_get_model_sym(ArithCoder *c, Model *m)
{
int idx, val;
@@ -268,289 +125,33 @@ static int arith_get_model_sym(ArithCoder *c, Model *m)
idx = arith_get_prob(c, m->cum_prob);

val = m->idx2sym[idx];
model_update(m, idx);
ff_mss12_model_update(m, idx);

arith_normalise(c);

return val;
}

static void pixctx_reset(PixContext *ctx)
{
int i, j, k;

for (i = 0; i < ctx->cache_size; i++)
ctx->cache[i] = i;

model_reset(&ctx->cache_model);
model_reset(&ctx->full_model);

for (i = 0; i < 4; i++)
for (j = 0; j < sec_order_sizes[i]; j++)
for (k = 0; k < 4; k++)
model_reset(&ctx->sec_models[i][j][k]);
}

static av_cold void pixctx_init(PixContext *ctx, int cache_size)
{
int i, j, k;

ctx->cache_size = cache_size + 4;
ctx->num_syms = cache_size;

for (i = 0; i < ctx->cache_size; i++)
ctx->cache[i] = i;

model_init(&ctx->cache_model, ctx->num_syms + 1, THRESH_LOW);
model_init(&ctx->full_model, 256, THRESH_HIGH);

for (i = 0; i < 4; i++) {
for (j = 0; j < sec_order_sizes[i]; j++) {
for (k = 0; k < 4; k++) {
model_init(&ctx->sec_models[i][j][k], 2 + i,
i ? THRESH_LOW : THRESH_ADAPTIVE);
}
}
}
}

static int decode_top_left_pixel(ArithCoder *acoder, PixContext *pctx)
{
int i, val, pix;

val = arith_get_model_sym(acoder, &pctx->cache_model);
if (val < pctx->num_syms) {
pix = pctx->cache[val];
} else {
pix = arith_get_model_sym(acoder, &pctx->full_model);
for (i = 0; i < pctx->cache_size - 1; i++)
if (pctx->cache[i] == pix)
break;
val = i;
}
if (val) {
for (i = val; i > 0; i--)
pctx->cache[i] = pctx->cache[i - 1];
pctx->cache[0] = pix;
}

return pix;
}

static int decode_pixel(ArithCoder *acoder, PixContext *pctx,
uint8_t *ngb, int num_ngb)
{
int i, val, pix;

val = arith_get_model_sym(acoder, &pctx->cache_model);
if (val < pctx->num_syms) {
int idx, j;


idx = 0;
for (i = 0; i < pctx->cache_size; i++) {
for (j = 0; j < num_ngb; j++)
if (pctx->cache[i] == ngb[j])
break;
if (j == num_ngb) {
if (idx == val)
break;
idx++;
}
}
val = FFMIN(i, pctx->cache_size - 1);
pix = pctx->cache[val];
} else {
pix = arith_get_model_sym(acoder, &pctx->full_model);
for (i = 0; i < pctx->cache_size - 1; i++)
if (pctx->cache[i] == pix)
break;
val = i;
}
if (val) {
for (i = val; i > 0; i--)
pctx->cache[i] = pctx->cache[i - 1];
pctx->cache[0] = pix;
}

return pix;
}

static int decode_pixel_in_context(ArithCoder *acoder, PixContext *pctx,
uint8_t *src, int stride, int x, int y,
int has_right)
{
uint8_t neighbours[4];
uint8_t ref_pix[4];
int nlen;
int layer = 0, sub;
int pix;
int i, j;

if (!y) {
memset(neighbours, src[-1], 4);
} else {
neighbours[TOP] = src[-stride];
if (!x) {
neighbours[TOP_LEFT] = neighbours[LEFT] = neighbours[TOP];
} else {
neighbours[TOP_LEFT] = src[-stride - 1];
neighbours[ LEFT] = src[-1];
}
if (has_right)
neighbours[TOP_RIGHT] = src[-stride + 1];
else
neighbours[TOP_RIGHT] = neighbours[TOP];
}

sub = 0;
if (x >= 2 && src[-2] == neighbours[LEFT])
sub = 1;
if (y >= 2 && src[-2 * stride] == neighbours[TOP])
sub |= 2;

nlen = 1;
ref_pix[0] = neighbours[0];
for (i = 1; i < 4; i++) {
for (j = 0; j < nlen; j++)
if (ref_pix[j] == neighbours[i])
break;
if (j == nlen)
ref_pix[nlen++] = neighbours[i];
}

switch (nlen) {
case 1:
case 4:
layer = 0;
break;
case 2:
if (neighbours[TOP] == neighbours[TOP_LEFT]) {
if (neighbours[TOP_RIGHT] == neighbours[TOP_LEFT])
layer = 3;
else if (neighbours[LEFT] == neighbours[TOP_LEFT])
layer = 2;
else
layer = 4;
} else if (neighbours[TOP_RIGHT] == neighbours[TOP_LEFT]) {
if (neighbours[LEFT] == neighbours[TOP_LEFT])
layer = 1;
else
layer = 5;
} else if (neighbours[LEFT] == neighbours[TOP_LEFT]) {
layer = 6;
} else {
layer = 0;
}
break;
case 3:
if (neighbours[TOP] == neighbours[TOP_LEFT])
layer = 0;
else if (neighbours[TOP_RIGHT] == neighbours[TOP_LEFT])
layer = 1;
else if (neighbours[LEFT] == neighbours[TOP_LEFT])
layer = 2;
else if (neighbours[TOP_RIGHT] == neighbours[TOP])
layer = 3;
else if (neighbours[TOP] == neighbours[LEFT])
layer = 4;
else
layer = 5;
break;
}

pix = arith_get_model_sym(acoder, &pctx->sec_models[nlen - 1][layer][sub]);
if (pix < nlen)
return ref_pix[pix];
else
return decode_pixel(acoder, pctx, ref_pix, nlen);
}

static int decode_region(MSS1Context *ctx, ArithCoder *acoder, uint8_t *dst,
int x, int y, int width, int height, int stride,
PixContext *pctx)
{
int i, j;

dst += x + y * stride;

dst[0] = decode_top_left_pixel(acoder, pctx);
for (j = 0; j < height; j++) {
for (i = 0; i < width; i++) {
if (!i && !j)
continue;

dst[i] = decode_pixel_in_context(acoder, pctx, dst + i, stride,
i, j, width - i - 1);
}
dst += stride;
}

return 0;
}

static int decode_region_masked(MSS1Context *ctx, ArithCoder *acoder,
uint8_t *dst, int stride, uint8_t *mask,
int mask_stride, int x, int y,
int width, int height,
PixContext *pctx)
{
int i, j;

dst += x + y * stride;
mask += x + y * mask_stride;

if (mask[0] == 0xFF)
dst[0] = decode_top_left_pixel(acoder, pctx);
for (j = 0; j < height; j++) {
for (i = 0; i < width; i++) {
if (!i && !j || mask[i] != 0xFF)
continue;

dst[i] = decode_pixel_in_context(acoder, pctx, dst + i, stride,
i, j, width - i - 1);
}
dst += stride;
mask += mask_stride;
}

return 0;
}

static av_cold void codec_init(MSS1Context *ctx)
static void arith_init(ArithCoder *c, GetBitContext *gb)
{
model_init(&ctx->intra_region, 2, THRESH_ADAPTIVE);
model_init(&ctx->inter_region, 2, THRESH_ADAPTIVE);
model_init(&ctx->split_mode, 3, THRESH_HIGH);
model_init(&ctx->edge_mode, 2, THRESH_HIGH);
model_init(&ctx->pivot, 3, THRESH_LOW);
pixctx_init(&ctx->intra_pix_ctx, 8);
pixctx_init(&ctx->inter_pix_ctx, 2);
ctx->corrupted = 1;
}
c->low = 0;
c->high = 0xFFFF;
c->value = get_bits(gb, 16);
c->gb = gb;

static void codec_reset(MSS1Context *ctx)
{
model_reset(&ctx->intra_region);
model_reset(&ctx->inter_region);
model_reset(&ctx->split_mode);
model_reset(&ctx->edge_mode);
model_reset(&ctx->pivot);
pixctx_reset(&ctx->intra_pix_ctx);
pixctx_reset(&ctx->inter_pix_ctx);

ctx->corrupted = 0;
c->get_model_sym = arith_get_model_sym;
c->get_number = arith_get_number;
}

static int decode_pal(MSS1Context *ctx, ArithCoder *acoder)
{
int i, ncol, r, g, b;
uint32_t *pal = ctx->pal + 256 - ctx->free_colours;
uint32_t *pal = ctx->ctx.pal + 256 - ctx->ctx.free_colours;

if (!ctx->free_colours)
if (!ctx->ctx.free_colours)
return 0;

ncol = arith_get_number(acoder, ctx->free_colours + 1);
ncol = arith_get_number(acoder, ctx->ctx.free_colours + 1);
for (i = 0; i < ncol; i++) {
r = arith_get_bits(acoder, 8);
g = arith_get_bits(acoder, 8);
@@ -561,119 +162,6 @@ static int decode_pal(MSS1Context *ctx, ArithCoder *acoder)
return !!ncol;
}

static int decode_pivot(MSS1Context *ctx, ArithCoder *acoder, int base)
{
int val, inv;

inv = arith_get_model_sym(acoder, &ctx->edge_mode);
val = arith_get_model_sym(acoder, &ctx->pivot) + 1;

if (val > 2) {
if ((base + 1) / 2 - 2 <= 0) {
ctx->corrupted = 1;
return 0;
}
val = arith_get_number(acoder, (base + 1) / 2 - 2) + 3;
}

if (val == base) {
ctx->corrupted = 1;
return 0;
}

return inv ? base - val : val;
}

static int decode_region_intra(MSS1Context *ctx, ArithCoder *acoder,
int x, int y, int width, int height)
{
int mode;

mode = arith_get_model_sym(acoder, &ctx->intra_region);

if (!mode) {
int i, pix;
int stride = ctx->pic_stride;
uint8_t *dst = ctx->pic_start + x + y * stride;

pix = decode_top_left_pixel(acoder, &ctx->intra_pix_ctx);
for (i = 0; i < height; i++, dst += stride)
memset(dst, pix, width);
} else {
return decode_region(ctx, acoder, ctx->pic_start,
x, y, width, height, ctx->pic_stride,
&ctx->intra_pix_ctx);
}

return 0;
}

static int decode_region_inter(MSS1Context *ctx, ArithCoder *acoder,
int x, int y, int width, int height)
{
int mode;

mode = arith_get_model_sym(acoder, &ctx->inter_region);

if (!mode) {
mode = decode_top_left_pixel(acoder, &ctx->inter_pix_ctx);
if (mode != 0xFF) {
return 0;
} else {
return decode_region_intra(ctx, acoder, x, y, width, height);
}
} else {
if (decode_region(ctx, acoder, ctx->mask,
x, y, width, height, ctx->mask_linesize,
&ctx->inter_pix_ctx) < 0)
return -1;
return decode_region_masked(ctx, acoder, ctx->pic_start,
-ctx->pic.linesize[0], ctx->mask,
ctx->mask_linesize,
x, y, width, height,
&ctx->intra_pix_ctx);
}

return 0;
}

static int decode_rect(MSS1Context *ctx, ArithCoder *acoder,
int x, int y, int width, int height)
{
int mode, pivot;

if (ctx->corrupted)
return -1;

mode = arith_get_model_sym(acoder, &ctx->split_mode);

switch (mode) {
case SPLIT_VERT:
pivot = decode_pivot(ctx, acoder, height);
if (decode_rect(ctx, acoder, x, y, width, pivot))
return -1;
if (decode_rect(ctx, acoder, x, y + pivot, width, height - pivot))
return -1;
break;
case SPLIT_HOR:
pivot = decode_pivot(ctx, acoder, width);
if (decode_rect(ctx, acoder, x, y, pivot, height))
return -1;
if (decode_rect(ctx, acoder, x + pivot, y, width - pivot, height))
return -1;
break;
case SPLIT_NONE:
if (ctx->keyframe)
return decode_region_intra(ctx, acoder, x, y, width, height);
else
return decode_region_inter(ctx, acoder, x, y, width, height);
default:
return -1;
}

return 0;
}

static int mss1_decode_frame(AVCodecContext *avctx, void *data, int *data_size,
AVPacket *avpkt)
{
@@ -696,24 +184,25 @@ static int mss1_decode_frame(AVCodecContext *avctx, void *data, int *data_size,
return ret;
}

c->pic_start = c->pic.data[0] + c->pic.linesize[0] * (avctx->height - 1);
c->pic_stride = -c->pic.linesize[0];
c->keyframe = !arith_get_bit(&acoder);
if (c->keyframe) {
codec_reset(c);
c->ctx.pic_start = c->pic.data[0] + c->pic.linesize[0] * (avctx->height - 1);
c->ctx.pic_stride = -c->pic.linesize[0];
c->ctx.keyframe = !arith_get_bit(&acoder);
if (c->ctx.keyframe) {
ff_mss12_codec_reset(&c->ctx);
pal_changed = decode_pal(c, &acoder);
c->pic.key_frame = 1;
c->pic.pict_type = AV_PICTURE_TYPE_I;
} else {
if (c->corrupted)
if (c->ctx.corrupted)
return AVERROR_INVALIDDATA;
c->pic.key_frame = 0;
c->pic.pict_type = AV_PICTURE_TYPE_P;
}
c->corrupted = decode_rect(c, &acoder, 0, 0, avctx->width, avctx->height);
if (c->corrupted)
c->ctx.corrupted = ff_mss12_decode_rect(&c->ctx, &acoder, 0, 0,
avctx->width, avctx->height);
if (c->ctx.corrupted)
return AVERROR_INVALIDDATA;
memcpy(c->pic.data[1], c->pal, AVPALETTE_SIZE);
memcpy(c->pic.data[1], c->ctx.pal, AVPALETTE_SIZE);
c->pic.palette_has_changed = pal_changed;

*data_size = sizeof(AVFrame);
@@ -726,69 +215,11 @@ static int mss1_decode_frame(AVCodecContext *avctx, void *data, int *data_size,
static av_cold int mss1_decode_init(AVCodecContext *avctx)
{
MSS1Context * const c = avctx->priv_data;
int i;

c->avctx = avctx;

if (avctx->extradata_size < 52 + 256 * 3) {
av_log(avctx, AV_LOG_ERROR, "Insufficient extradata size %d\n",
avctx->extradata_size);
return AVERROR_INVALIDDATA;
}

if (AV_RB32(avctx->extradata) < avctx->extradata_size) {
av_log(avctx, AV_LOG_ERROR,
"Insufficient extradata size: expected %d got %d\n",
AV_RB32(avctx->extradata),
avctx->extradata_size);
return AVERROR_INVALIDDATA;
}

av_log(avctx, AV_LOG_DEBUG, "Encoder version %d.%d\n",
AV_RB32(avctx->extradata + 4), AV_RB32(avctx->extradata + 8));
c->free_colours = AV_RB32(avctx->extradata + 48);
if ((unsigned)c->free_colours > 256) {
av_log(avctx, AV_LOG_ERROR,
"Incorrect number of changeable palette entries: %d\n",
c->free_colours);
return AVERROR_INVALIDDATA;
}
av_log(avctx, AV_LOG_DEBUG, "%d free colour(s)\n", c->free_colours);
avctx->coded_width = AV_RB32(avctx->extradata + 20);
avctx->coded_height = AV_RB32(avctx->extradata + 24);

av_log(avctx, AV_LOG_DEBUG, "Display dimensions %dx%d\n",
AV_RB32(avctx->extradata + 12), AV_RB32(avctx->extradata + 16));
av_log(avctx, AV_LOG_DEBUG, "Coded dimensions %dx%d\n",
avctx->coded_width, avctx->coded_height);
av_log(avctx, AV_LOG_DEBUG, "%g frames per second\n",
av_int2float(AV_RB32(avctx->extradata + 28)));
av_log(avctx, AV_LOG_DEBUG, "Bitrate %d bps\n",
AV_RB32(avctx->extradata + 32));
av_log(avctx, AV_LOG_DEBUG, "Max. lead time %g ms\n",
av_int2float(AV_RB32(avctx->extradata + 36)));
av_log(avctx, AV_LOG_DEBUG, "Max. lag time %g ms\n",
av_int2float(AV_RB32(avctx->extradata + 40)));
av_log(avctx, AV_LOG_DEBUG, "Max. seek time %g ms\n",
av_int2float(AV_RB32(avctx->extradata + 44)));

for (i = 0; i < 256; i++)
c->pal[i] = AV_RB24(avctx->extradata + 52 + i * 3);

avctx->pix_fmt = PIX_FMT_PAL8;

c->mask_linesize = FFALIGN(avctx->width, 16);
c->mask = av_malloc(c->mask_linesize * avctx->height);
if (!c->mask) {
av_log(avctx, AV_LOG_ERROR, "Cannot allocate mask plane\n");
return AVERROR(ENOMEM);
}

c->ctx.avctx = avctx;
avctx->coded_frame = &c->pic;

codec_init(c);

return 0;
return ff_mss12_decode_init(avctx, 0);
}

static av_cold int mss1_decode_end(AVCodecContext *avctx)
@@ -797,7 +228,7 @@ static av_cold int mss1_decode_end(AVCodecContext *avctx)

if (c->pic.data[0])
avctx->release_buffer(avctx, &c->pic);
av_freep(&c->mask);
ff_mss12_decode_end(avctx);

return 0;
}


+ 581
- 0
libavcodec/mss12.c View File

@@ -0,0 +1,581 @@
/*
* Copyright (c) 2012 Konstantin Shishkov
*
* This file is part of Libav.
*
* Libav 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.
*
* Libav 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 Libav; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/

/**
* @file
* Common functions for Microsoft Screen 1 and 2
*/

#include "libavutil/intfloat.h"
#include "libavutil/intreadwrite.h"
#include "avcodec.h"
#include "mss12.h"

enum SplitMode {
SPLIT_VERT = 0,
SPLIT_HOR,
SPLIT_NONE
};

static const int sec_order_sizes[4] = { 1, 7, 6, 1 };

enum ContextDirection {
TOP_LEFT = 0,
TOP,
TOP_RIGHT,
LEFT
};

static int model_calc_threshold(Model *m)
{
int thr;

if (m->thr_weight == -1) {
thr = 2 * m->weights[m->num_syms] - 1;
thr = ((thr >> 1) + 4 * m->cum_prob[0]) / thr;
} else {
thr = m->num_syms * m->thr_weight;
}

return FFMIN(thr, 0x3FFF);
}

static void model_reset(Model *m)
{
int i;

for (i = 0; i <= m->num_syms; i++) {
m->weights[i] = 1;
m->cum_prob[i] = m->num_syms - i;
}
m->weights[0] = -1;
m->idx2sym[0] = -1;
m->sym2idx[m->num_syms] = -1;
for (i = 0; i < m->num_syms; i++) {
m->sym2idx[i] = i + 1;
m->idx2sym[i + 1] = i;
}
}

static av_cold void model_init(Model *m, int num_syms, int thr_weight)
{
m->num_syms = num_syms;
m->thr_weight = thr_weight;
m->threshold = model_calc_threshold(m);
model_reset(m);
}

static void model_rescale_weights(Model *m)
{
int i;
int cum_prob;

if (m->thr_weight == -1)
m->threshold = model_calc_threshold(m);
while (m->cum_prob[0] > m->threshold) {
cum_prob = 0;
for (i = m->num_syms; i >= 0; i--) {
m->cum_prob[i] = cum_prob;
m->weights[i] = (m->weights[i] + 1) >> 1;
cum_prob += m->weights[i];
}
}
}

void ff_mss12_model_update(Model *m, int val)
{
int i;

if (m->weights[val] == m->weights[val - 1]) {
for (i = val; m->weights[i - 1] == m->weights[val]; i--);
if (i != val) {
int sym1, sym2;

sym1 = m->idx2sym[val];
sym2 = m->idx2sym[i];

m->idx2sym[val] = sym2;
m->idx2sym[i] = sym1;
m->sym2idx[sym1] = i;
m->sym2idx[sym2] = val;

val = i;
}
}
m->weights[val]++;
for (i = val - 1; i >= 0; i--)
m->cum_prob[i]++;
model_rescale_weights(m);
}

static void pixctx_reset(PixContext *ctx)
{
int i, j, k;

for (i = 0; i < ctx->cache_size; i++)
ctx->cache[i] = i;

model_reset(&ctx->cache_model);
model_reset(&ctx->full_model);

for (i = 0; i < 4; i++)
for (j = 0; j < sec_order_sizes[i]; j++)
for (k = 0; k < 4; k++)
model_reset(&ctx->sec_models[i][j][k]);
}

static av_cold void pixctx_init(PixContext *ctx, int cache_size)
{
int i, j, k;

ctx->cache_size = cache_size + 4;
ctx->num_syms = cache_size;

for (i = 0; i < ctx->cache_size; i++)
ctx->cache[i] = i;

model_init(&ctx->cache_model, ctx->num_syms + 1, THRESH_LOW);
model_init(&ctx->full_model, 256, THRESH_HIGH);

for (i = 0; i < 4; i++) {
for (j = 0; j < sec_order_sizes[i]; j++) {
for (k = 0; k < 4; k++) {
model_init(&ctx->sec_models[i][j][k], 2 + i,
i ? THRESH_LOW : THRESH_ADAPTIVE);
}
}
}
}

static int decode_top_left_pixel(ArithCoder *acoder, PixContext *pctx)
{
int i, val, pix;

val = acoder->get_model_sym(acoder, &pctx->cache_model);
if (val < pctx->num_syms) {
pix = pctx->cache[val];
} else {
pix = acoder->get_model_sym(acoder, &pctx->full_model);
for (i = 0; i < pctx->cache_size - 1; i++)
if (pctx->cache[i] == pix)
break;
val = i;
}
if (val) {
for (i = val; i > 0; i--)
pctx->cache[i] = pctx->cache[i - 1];
pctx->cache[0] = pix;
}

return pix;
}

static int decode_pixel(ArithCoder *acoder, PixContext *pctx,
uint8_t *ngb, int num_ngb)
{
int i, val, pix;

val = acoder->get_model_sym(acoder, &pctx->cache_model);
if (val < pctx->num_syms) {
int idx, j;


idx = 0;
for (i = 0; i < pctx->cache_size; i++) {
for (j = 0; j < num_ngb; j++)
if (pctx->cache[i] == ngb[j])
break;
if (j == num_ngb) {
if (idx == val)
break;
idx++;
}
}
val = FFMIN(i, pctx->cache_size - 1);
pix = pctx->cache[val];
} else {
pix = acoder->get_model_sym(acoder, &pctx->full_model);
for (i = 0; i < pctx->cache_size - 1; i++)
if (pctx->cache[i] == pix)
break;
val = i;
}
if (val) {
for (i = val; i > 0; i--)
pctx->cache[i] = pctx->cache[i - 1];
pctx->cache[0] = pix;
}

return pix;
}

static int decode_pixel_in_context(ArithCoder *acoder, PixContext *pctx,
uint8_t *src, int stride, int x, int y,
int has_right)
{
uint8_t neighbours[4];
uint8_t ref_pix[4];
int nlen;
int layer = 0, sub;
int pix;
int i, j;

if (!y) {
memset(neighbours, src[-1], 4);
} else {
neighbours[TOP] = src[-stride];
if (!x) {
neighbours[TOP_LEFT] = neighbours[LEFT] = neighbours[TOP];
} else {
neighbours[TOP_LEFT] = src[-stride - 1];
neighbours[ LEFT] = src[-1];
}
if (has_right)
neighbours[TOP_RIGHT] = src[-stride + 1];
else
neighbours[TOP_RIGHT] = neighbours[TOP];
}

sub = 0;
if (x >= 2 && src[-2] == neighbours[LEFT])
sub = 1;
if (y >= 2 && src[-2 * stride] == neighbours[TOP])
sub |= 2;

nlen = 1;
ref_pix[0] = neighbours[0];
for (i = 1; i < 4; i++) {
for (j = 0; j < nlen; j++)
if (ref_pix[j] == neighbours[i])
break;
if (j == nlen)
ref_pix[nlen++] = neighbours[i];
}

switch (nlen) {
case 1:
case 4:
layer = 0;
break;
case 2:
if (neighbours[TOP] == neighbours[TOP_LEFT]) {
if (neighbours[TOP_RIGHT] == neighbours[TOP_LEFT])
layer = 3;
else if (neighbours[LEFT] == neighbours[TOP_LEFT])
layer = 2;
else
layer = 4;
} else if (neighbours[TOP_RIGHT] == neighbours[TOP_LEFT]) {
if (neighbours[LEFT] == neighbours[TOP_LEFT])
layer = 1;
else
layer = 5;
} else if (neighbours[LEFT] == neighbours[TOP_LEFT]) {
layer = 6;
} else {
layer = 0;
}
break;
case 3:
if (neighbours[TOP] == neighbours[TOP_LEFT])
layer = 0;
else if (neighbours[TOP_RIGHT] == neighbours[TOP_LEFT])
layer = 1;
else if (neighbours[LEFT] == neighbours[TOP_LEFT])
layer = 2;
else if (neighbours[TOP_RIGHT] == neighbours[TOP])
layer = 3;
else if (neighbours[TOP] == neighbours[LEFT])
layer = 4;
else
layer = 5;
break;
}

pix = acoder->get_model_sym(acoder, &pctx->sec_models[nlen - 1][layer][sub]);
if (pix < nlen)
return ref_pix[pix];
else
return decode_pixel(acoder, pctx, ref_pix, nlen);
}

static int decode_region(MSS12Context *ctx, ArithCoder *acoder, uint8_t *dst,
int x, int y, int width, int height, int stride,
PixContext *pctx)
{
int i, j;

dst += x + y * stride;

dst[0] = decode_top_left_pixel(acoder, pctx);
for (j = 0; j < height; j++) {
for (i = 0; i < width; i++) {
if (!i && !j)
continue;

dst[i] = decode_pixel_in_context(acoder, pctx, dst + i, stride,
i, j, width - i - 1);
}
dst += stride;
}

return 0;
}

static int decode_region_masked(MSS12Context *ctx, ArithCoder *acoder,
uint8_t *dst, int stride, uint8_t *mask,
int mask_stride, int x, int y,
int width, int height,
PixContext *pctx)
{
int i, j;

dst += x + y * stride;
mask += x + y * mask_stride;

if (mask[0] == 0xFF)
dst[0] = decode_top_left_pixel(acoder, pctx);
for (j = 0; j < height; j++) {
for (i = 0; i < width; i++) {
if (!i && !j || mask[i] != 0xFF)
continue;

dst[i] = decode_pixel_in_context(acoder, pctx, dst + i, stride,
i, j, width - i - 1);
}
dst += stride;
mask += mask_stride;
}

return 0;
}

static av_cold void codec_init(MSS12Context *ctx)
{
model_init(&ctx->intra_region, 2, THRESH_ADAPTIVE);
model_init(&ctx->inter_region, 2, THRESH_ADAPTIVE);
model_init(&ctx->split_mode, 3, THRESH_HIGH);
model_init(&ctx->edge_mode, 2, THRESH_HIGH);
model_init(&ctx->pivot, 3, THRESH_LOW);
pixctx_init(&ctx->intra_pix_ctx, 8);
pixctx_init(&ctx->inter_pix_ctx, 2);
ctx->corrupted = 1;
}

void ff_mss12_codec_reset(MSS12Context *ctx)
{
model_reset(&ctx->intra_region);
model_reset(&ctx->inter_region);
model_reset(&ctx->split_mode);
model_reset(&ctx->edge_mode);
model_reset(&ctx->pivot);
pixctx_reset(&ctx->intra_pix_ctx);
pixctx_reset(&ctx->inter_pix_ctx);

ctx->corrupted = 0;
}

static int decode_pivot(MSS12Context *ctx, ArithCoder *acoder, int base)
{
int val, inv;

inv = acoder->get_model_sym(acoder, &ctx->edge_mode);
val = acoder->get_model_sym(acoder, &ctx->pivot) + 1;

if (val > 2) {
if ((base + 1) / 2 - 2 <= 0) {
ctx->corrupted = 1;
return 0;
}
val = acoder->get_number(acoder, (base + 1) / 2 - 2) + 3;
}

if (val == base) {
ctx->corrupted = 1;
return 0;
}

return inv ? base - val : val;
}

static int decode_region_intra(MSS12Context *ctx, ArithCoder *acoder,
int x, int y, int width, int height)
{
int mode;

mode = acoder->get_model_sym(acoder, &ctx->intra_region);

if (!mode) {
int i, pix;
int stride = ctx->pic_stride;
uint8_t *dst = ctx->pic_start + x + y * stride;

pix = decode_top_left_pixel(acoder, &ctx->intra_pix_ctx);
for (i = 0; i < height; i++, dst += stride)
memset(dst, pix, width);
} else {
return decode_region(ctx, acoder, ctx->pic_start,
x, y, width, height, ctx->pic_stride,
&ctx->intra_pix_ctx);
}

return 0;
}

static int decode_region_inter(MSS12Context *ctx, ArithCoder *acoder,
int x, int y, int width, int height)
{
int mode;

mode = acoder->get_model_sym(acoder, &ctx->inter_region);

if (!mode) {
mode = decode_top_left_pixel(acoder, &ctx->inter_pix_ctx);
if (mode != 0xFF) {
return 0;
} else {
return decode_region_intra(ctx, acoder, x, y, width, height);
}
} else {
if (decode_region(ctx, acoder, ctx->mask,
x, y, width, height, ctx->mask_linesize,
&ctx->inter_pix_ctx) < 0)
return -1;
return decode_region_masked(ctx, acoder, ctx->pic_start,
ctx->pic_stride, ctx->mask,
ctx->mask_linesize,
x, y, width, height,
&ctx->intra_pix_ctx);
}

return 0;
}

int ff_mss12_decode_rect(MSS12Context *ctx, ArithCoder *acoder,
int x, int y, int width, int height)
{
int mode, pivot;

if (ctx->corrupted)
return -1;

mode = acoder->get_model_sym(acoder, &ctx->split_mode);

switch (mode) {
case SPLIT_VERT:
pivot = decode_pivot(ctx, acoder, height);
if (ff_mss12_decode_rect(ctx, acoder, x, y, width, pivot))
return -1;
if (ff_mss12_decode_rect(ctx, acoder, x, y + pivot, width, height - pivot))
return -1;
break;
case SPLIT_HOR:
pivot = decode_pivot(ctx, acoder, width);
if (ff_mss12_decode_rect(ctx, acoder, x, y, pivot, height))
return -1;
if (ff_mss12_decode_rect(ctx, acoder, x + pivot, y, width - pivot, height))
return -1;
break;
case SPLIT_NONE:
if (ctx->keyframe)
return decode_region_intra(ctx, acoder, x, y, width, height);
else
return decode_region_inter(ctx, acoder, x, y, width, height);
default:
return -1;
}

return 0;
}

av_cold int ff_mss12_decode_init(AVCodecContext *avctx, int version)
{
MSS12Context * const c = avctx->priv_data;
int i;

c->avctx = avctx;

if (avctx->extradata_size < 52 + 256 * 3) {
av_log(avctx, AV_LOG_ERROR, "Insufficient extradata size %d\n",
avctx->extradata_size);
return AVERROR_INVALIDDATA;
}

if (AV_RB32(avctx->extradata) < avctx->extradata_size) {
av_log(avctx, AV_LOG_ERROR,
"Insufficient extradata size: expected %d got %d\n",
AV_RB32(avctx->extradata),
avctx->extradata_size);
return AVERROR_INVALIDDATA;
}

av_log(avctx, AV_LOG_DEBUG, "Encoder version %d.%d\n",
AV_RB32(avctx->extradata + 4), AV_RB32(avctx->extradata + 8));
c->free_colours = AV_RB32(avctx->extradata + 48);
if ((unsigned)c->free_colours > 256) {
av_log(avctx, AV_LOG_ERROR,
"Incorrect number of changeable palette entries: %d\n",
c->free_colours);
return AVERROR_INVALIDDATA;
}
av_log(avctx, AV_LOG_DEBUG, "%d free colour(s)\n", c->free_colours);
avctx->coded_width = AV_RB32(avctx->extradata + 20);
avctx->coded_height = AV_RB32(avctx->extradata + 24);

av_log(avctx, AV_LOG_DEBUG, "Display dimensions %dx%d\n",
AV_RB32(avctx->extradata + 12), AV_RB32(avctx->extradata + 16));
av_log(avctx, AV_LOG_DEBUG, "Coded dimensions %dx%d\n",
avctx->coded_width, avctx->coded_height);
av_log(avctx, AV_LOG_DEBUG, "%g frames per second\n",
av_int2float(AV_RB32(avctx->extradata + 28)));
av_log(avctx, AV_LOG_DEBUG, "Bitrate %d bps\n",
AV_RB32(avctx->extradata + 32));
av_log(avctx, AV_LOG_DEBUG, "Max. lead time %g ms\n",
av_int2float(AV_RB32(avctx->extradata + 36)));
av_log(avctx, AV_LOG_DEBUG, "Max. lag time %g ms\n",
av_int2float(AV_RB32(avctx->extradata + 40)));
av_log(avctx, AV_LOG_DEBUG, "Max. seek time %g ms\n",
av_int2float(AV_RB32(avctx->extradata + 44)));

for (i = 0; i < 256; i++)
c->pal[i] = AV_RB24(avctx->extradata + 52 + i * 3);

avctx->pix_fmt = PIX_FMT_PAL8;

c->mask_linesize = FFALIGN(avctx->width, 16);
c->mask = av_malloc(c->mask_linesize * avctx->height);
if (!c->mask) {
av_log(avctx, AV_LOG_ERROR, "Cannot allocate mask plane\n");
return AVERROR(ENOMEM);
}

codec_init(c);

return 0;
}

av_cold int ff_mss12_decode_end(AVCodecContext *avctx)
{
MSS12Context * const c = avctx->priv_data;

av_freep(&c->mask);

return 0;
}

+ 83
- 0
libavcodec/mss12.h View File

@@ -0,0 +1,83 @@
/*
* Copyright (c) 2012 Konstantin Shishkov
*
* This file is part of Libav.
*
* Libav 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.
*
* Libav 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 Libav; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/

/**
* @file
* Common header for Microsoft Screen 1 and 2
*/

#ifndef AVCODEC_MSS12_H
#define AVCODEC_MSS12_H

#include "avcodec.h"
#include "get_bits.h"

#define MODEL_MIN_SYMS 2
#define MODEL_MAX_SYMS 256
#define THRESH_ADAPTIVE -1
#define THRESH_LOW 15
#define THRESH_HIGH 50

typedef struct Model {
int cum_prob[MODEL_MAX_SYMS + 1];
int weights[MODEL_MAX_SYMS + 1];
int idx2sym[MODEL_MAX_SYMS + 1];
int sym2idx[MODEL_MAX_SYMS + 1];
int num_syms;
int thr_weight, threshold;
} Model;

typedef struct ArithCoder {
int low, high, value;
GetBitContext *gb;
int (*get_model_sym)(struct ArithCoder *c, Model *m);
int (*get_number) (struct ArithCoder *c, int n);
} ArithCoder;

typedef struct PixContext {
int cache_size, num_syms;
uint8_t cache[12];
Model cache_model, full_model;
Model sec_models[4][8][4];
} PixContext;

typedef struct MSS12Context {
AVCodecContext *avctx;
uint8_t *pic_start;
int pic_stride;
uint8_t *mask;
int mask_linesize;
uint32_t pal[256];
int free_colours;
int keyframe;
Model intra_region, inter_region;
Model pivot, edge_mode, split_mode;
PixContext intra_pix_ctx, inter_pix_ctx;
int corrupted;
} MSS12Context;

int ff_mss12_decode_rect(MSS12Context *ctx, ArithCoder *acoder,
int x, int y, int width, int height);
void ff_mss12_model_update(Model *m, int val);
void ff_mss12_codec_reset(MSS12Context *ctx);
av_cold int ff_mss12_decode_init(AVCodecContext *avctx, int version);
av_cold int ff_mss12_decode_end(AVCodecContext *avctx);

#endif /* AVCODEC_MSS12_H */

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