Commit 40d26273 authored by Eli Friedman's avatar Eli Friedman Committed by Robert Swain
Browse files

Escape 124 (RPL) decoder

Patch by Eli Friedman (eli friedman gmail com)

Originally committed as revision 12648 to svn://svn.ffmpeg.org/ffmpeg/trunk
parent 7542157d
......@@ -67,6 +67,7 @@ OBJS-$(CONFIG_DXA_DECODER) += dxa.o
OBJS-$(CONFIG_EIGHTBPS_DECODER) += 8bps.o
OBJS-$(CONFIG_EIGHTSVX_EXP_DECODER) += 8svx.o
OBJS-$(CONFIG_EIGHTSVX_FIB_DECODER) += 8svx.o
OBJS-$(CONFIG_ESCAPE124_DECODER) += escape124.o
OBJS-$(CONFIG_FFV1_DECODER) += ffv1.o rangecoder.o golomb.o
OBJS-$(CONFIG_FFV1_ENCODER) += ffv1.o rangecoder.o
OBJS-$(CONFIG_FFVHUFF_DECODER) += huffyuv.o
......
......@@ -80,6 +80,7 @@ void avcodec_register_all(void)
REGISTER_DECODER (EIGHTBPS, eightbps);
REGISTER_DECODER (EIGHTSVX_EXP, eightsvx_exp);
REGISTER_DECODER (EIGHTSVX_FIB, eightsvx_fib);
REGISTER_DECODER (ESCAPE124, escape124);
REGISTER_ENCDEC (FFV1, ffv1);
REGISTER_ENCDEC (FFVHUFF, ffvhuff);
REGISTER_ENCDEC (FLASHSV, flashsv);
......
......@@ -181,6 +181,7 @@ enum CodecID {
CODEC_ID_RL2,
CODEC_ID_8SVX_EXP,
CODEC_ID_8SVX_FIB,
CODEC_ID_ESCAPE124,
/* various PCM "codecs" */
CODEC_ID_PCM_S16LE= 0x10000,
......
/*
* Escape 124 Video Decoder
* Copyright (C) 2008 Eli Friedman (eli.friedman@gmail.com)
*
* 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"
#define ALT_BITSTREAM_READER_LE
#include "bitstream.h"
typedef union MacroBlock {
uint16_t pixels[4];
uint32_t pixels32[2];
} MacroBlock;
typedef union SuperBlock {
uint16_t pixels[64];
uint32_t pixels32[32];
} SuperBlock;
typedef struct CodeBook {
unsigned depth;
unsigned size;
MacroBlock blocks[];
} CodeBook;
typedef struct Escape124Context {
AVFrame frame;
unsigned num_superblocks;
CodeBook* codebooks[3];
} Escape124Context;
static int can_safely_read(GetBitContext* gb, int bits) {
return get_bits_count(gb) + bits <= gb->size_in_bits;
}
/**
* Initialize the decoder
* @param avctx decoder context
* @return 0 success, negative on error
*/
static av_cold int escape124_decode_init(AVCodecContext *avctx)
{
Escape124Context *s = avctx->priv_data;
avctx->pix_fmt = PIX_FMT_RGB555;
s->num_superblocks = ((unsigned)avctx->width / 8) *
((unsigned)avctx->height / 8);
return 0;
}
static av_cold int escape124_decode_close(AVCodecContext *avctx)
{
unsigned i;
Escape124Context *s = avctx->priv_data;
for (i = 0; i < 3; i++)
av_free(s->codebooks[i]);
if (s->frame.data[0])
avctx->release_buffer(avctx, &s->frame);
return 0;
}
static CodeBook* unpack_codebook(GetBitContext* gb, unsigned depth,
unsigned size)
{
unsigned i, j;
CodeBook* cb;
if (!can_safely_read(gb, size * 34))
return NULL;
if (size >= (INT_MAX - sizeof(CodeBook)) / sizeof(MacroBlock))
return NULL;
cb = av_malloc(size * sizeof(MacroBlock) + sizeof(CodeBook));
if (!cb)
return NULL;
cb->depth = depth;
cb->size = size;
for (i = 0; i < size; i++) {
unsigned mask_bits = get_bits(gb, 4);
unsigned color0 = get_bits(gb, 15);
unsigned color1 = get_bits(gb, 15);
for (j = 0; j < 4; j++) {
if (mask_bits & (1 << j))
cb->blocks[i].pixels[j] = color1;
else
cb->blocks[i].pixels[j] = color0;
}
}
return cb;
}
static unsigned decode_skip_count(GetBitContext* gb)
{
unsigned value;
// This function reads a maximum of 23 bits,
// which is within the padding space
if (!can_safely_read(gb, 1))
return -1;
value = get_bits1(gb);
if (!value)
return value;
value += get_bits(gb, 3);
if (value != (1 + ((1 << 3) - 1)))
return value;
value += get_bits(gb, 7);
if (value != (1 + ((1 << 3) - 1)) + ((1 << 7) - 1))
return value;
return value + get_bits(gb, 12);
}
static MacroBlock decode_macroblock(Escape124Context* s, GetBitContext* gb,
int* codebook_index, int superblock_index)
{
// This function reads a maximum of 22 bits; the callers
// guard this function appropriately
unsigned block_index, depth;
if (get_bits1(gb)) {
static const char transitions[3][2] = { {2, 1}, {0, 2}, {1, 0} };
*codebook_index = transitions[*codebook_index][get_bits1(gb)];
}
depth = s->codebooks[*codebook_index]->depth;
// depth = 0 means that this shouldn't read any bits;
// in theory, this is the same as get_bits(gb, 0), but
// that doesn't actually work.
block_index = depth ? get_bits(gb, depth) : 0;
if (*codebook_index == 1) {
block_index += superblock_index << s->codebooks[1]->depth;
}
// This condition can occur with invalid bitstreams and
// *codebook_index == 2
if (block_index >= s->codebooks[*codebook_index]->size)
return (MacroBlock) { { 0 } };
return s->codebooks[*codebook_index]->blocks[block_index];
}
static void insert_mb_into_sb(SuperBlock* sb, MacroBlock mb, unsigned index) {
// Formula: ((index / 4) * 16 + (index % 4) * 2) / 2
uint32_t *dst = sb->pixels32 + index + (index & -4);
// This technically violates C99 aliasing rules, but it should be safe.
dst[0] = mb.pixels32[0];
dst[4] = mb.pixels32[1];
}
static void copy_superblock(uint16_t* dest, unsigned dest_stride,
uint16_t* src, unsigned src_stride)
{
unsigned y;
if (src)
for (y = 0; y < 8; y++)
memcpy(dest + y * dest_stride, src + y * src_stride,
sizeof(uint16_t) * 8);
else
for (y = 0; y < 8; y++)
memset(dest + y * dest_stride, 0, sizeof(uint16_t) * 8);
}
static const uint16_t mask_matrix[] = {0x1, 0x2, 0x10, 0x20,
0x4, 0x8, 0x40, 0x80,
0x100, 0x200, 0x1000, 0x2000,
0x400, 0x800, 0x4000, 0x8000};
/**
* Decode a single frame
* @param avctx decoder context
* @param data decoded frame
* @param data_size size of the decoded frame
* @param buf input buffer
* @param buf_size input buffer size
* @return 0 success, -1 on error
*/
static int escape124_decode_frame(AVCodecContext *avctx,
void *data, int *data_size,
const uint8_t *buf, int buf_size)
{
Escape124Context *s = avctx->priv_data;
GetBitContext gb;
unsigned frame_flags, frame_size;
unsigned i;
unsigned superblock_index, cb_index = 1,
superblock_col_index = 0,
superblocks_per_row = avctx->width / 8, skip = -1;
uint16_t* old_frame_data, *new_frame_data;
unsigned old_stride, new_stride;
AVFrame new_frame = { { 0 } };
init_get_bits(&gb, buf, buf_size * 8);
// This call also guards the potential depth reads for the
// codebook unpacking.
if (!can_safely_read(&gb, 64))
return -1;
frame_flags = get_bits_long(&gb, 32);
frame_size = get_bits_long(&gb, 32);
// Leave last frame unchanged
// FIXME: Is this necessary? I haven't seen it in any real samples
if (!(frame_flags & 0x114) || !(frame_flags & 0x7800000)) {
av_log(NULL, AV_LOG_DEBUG, "Skipping frame\n");
*data_size = sizeof(AVFrame);
*(AVFrame*)data = s->frame;
return frame_size;
}
for (i = 0; i < 3; i++) {
if (frame_flags & (1 << (17 + i))) {
unsigned cb_depth, cb_size;
if (i == 2) {
// This codebook can be cut off at places other than
// powers of 2, leaving some of the entries undefined.
cb_size = get_bits_long(&gb, 20);
cb_depth = av_log2(cb_size - 1) + 1;
} else {
cb_depth = get_bits(&gb, 4);
if (i == 0) {
// This is the most basic codebook: pow(2,depth) entries
// for a depth-length key
cb_size = 1 << cb_depth;
} else {
// This codebook varies per superblock
// FIXME: I don't think this handles integer overflow
// properly
cb_size = s->num_superblocks << cb_depth;
}
}
av_free(s->codebooks[i]);
s->codebooks[i] = unpack_codebook(&gb, cb_depth, cb_size);
if (!s->codebooks[i])
return -1;
}
}
new_frame.reference = 3;
if (avctx->get_buffer(avctx, &new_frame)) {
av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
return -1;
}
new_frame_data = (uint16_t*)new_frame.data[0];
new_stride = new_frame.linesize[0] / 2;
old_frame_data = (uint16_t*)s->frame.data[0];
old_stride = s->frame.linesize[0] / 2;
for (superblock_index = 0; superblock_index < s->num_superblocks;
superblock_index++) {
MacroBlock mb;
SuperBlock sb;
unsigned multi_mask = 0;
if (skip == -1) {
// Note that this call will make us skip the rest of the blocks
// if the frame prematurely ends
skip = decode_skip_count(&gb);
}
if (skip) {
copy_superblock(new_frame_data, new_stride,
old_frame_data, old_stride);
} else {
copy_superblock(sb.pixels, 8,
old_frame_data, old_stride);
while (can_safely_read(&gb, 1) && !get_bits1(&gb)) {
unsigned mask;
mb = decode_macroblock(s, &gb, &cb_index, superblock_index);
mask = get_bits(&gb, 16);
multi_mask |= mask;
for (i = 0; i < 16; i++) {
if (mask & mask_matrix[i]) {
insert_mb_into_sb(&sb, mb, i);
}
}
}
if (can_safely_read(&gb, 1) && !get_bits1(&gb)) {
unsigned inv_mask = get_bits(&gb, 4);
for (i = 0; i < 4; i++) {
if (inv_mask & (1 << i)) {
multi_mask ^= 0xF << i*4;
} else {
multi_mask ^= get_bits(&gb, 4) << i*4;
}
}
for (i = 0; i < 16; i++) {
if (multi_mask & mask_matrix[i]) {
if (!can_safely_read(&gb, 1))
break;
mb = decode_macroblock(s, &gb, &cb_index,
superblock_index);
insert_mb_into_sb(&sb, mb, i);
}
}
} else if (frame_flags & (1 << 16)) {
while (can_safely_read(&gb, 1) && !get_bits1(&gb)) {
mb = decode_macroblock(s, &gb, &cb_index, superblock_index);
insert_mb_into_sb(&sb, mb, get_bits(&gb, 4));
}
}
copy_superblock(new_frame_data, new_stride, sb.pixels, 8);
}
superblock_col_index++;
new_frame_data += 8;
if (old_frame_data)
old_frame_data += 8;
if (superblock_col_index == superblocks_per_row) {
new_frame_data += new_stride * 8 - superblocks_per_row * 8;
if (old_frame_data)
old_frame_data += old_stride * 8 - superblocks_per_row * 8;
superblock_col_index = 0;
}
skip--;
}
av_log(NULL, AV_LOG_DEBUG,
"Escape sizes: %i, %i, %i\n",
frame_size, buf_size, get_bits_count(&gb) / 8);
if (s->frame.data[0])
avctx->release_buffer(avctx, &s->frame);
*(AVFrame*)data = s->frame = new_frame;
*data_size = sizeof(AVFrame);
return frame_size;
}
AVCodec escape124_decoder = {
"escape124",
CODEC_TYPE_VIDEO,
CODEC_ID_ESCAPE124,
sizeof(Escape124Context),
escape124_decode_init,
NULL,
escape124_decode_close,
escape124_decode_frame,
CODEC_CAP_DR1,
};
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