static CodeBook unpack_codebook(GetBitContext* gb, unsigned depth,
unsigned size)
{
unsigned i, j;
CodeBook cb = { 0 };
if (!can_safely_read(gb, size * 34))
return cb;
if (size >= INT_MAX / sizeof(MacroBlock))
return cb;
cb.blocks = av_malloc(size ? size * sizeof(MacroBlock) : 1);
if (!cb.blocks)
return cb;
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 int GetLine( T* p, lua_State *L )
{
can_safely_read(p, L);
RString string;
p->GetLine(string);
lua_pushstring( L, string );
return 1;
}
static int ReadBytes( T* p, lua_State *L )
{
can_safely_read(p, L);
RString string;
p->Read( string, IArg(1) );
lua_pushstring( L, string );
return 1;
}
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 int AtEOF( T* p, lua_State *L )
{
can_safely_read(p, L);
lua_pushboolean( L, p->AtEOF() );
return 1;
}
static int Tell( T* p, lua_State *L )
{
can_safely_read(p, L);
lua_pushinteger( L, p->Tell() );
return 1;
}
static int Seek( T* p, lua_State *L )
{
can_safely_read(p, L);
lua_pushinteger( L, p->Seek( IArg(1) ) );
return 1;
}
static int escape124_decode_frame(AVCodecContext *avctx,
void *data, int *got_frame,
AVPacket *avpkt)
{
const uint8_t *buf = avpkt->data;
int buf_size = avpkt->size;
Escape124Context *s = avctx->priv_data;
AVFrame *frame = 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;
int ret;
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)) {
if (!s->frame->data[0])
return AVERROR_INVALIDDATA;
av_log(NULL, AV_LOG_DEBUG, "Skipping frame\n");
*got_frame = 1;
if ((ret = av_frame_ref(frame, s->frame)) < 0)
return ret;
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].blocks);
s->codebooks[i] = unpack_codebook(&gb, cb_depth, cb_size);
if (!s->codebooks[i].blocks)
return -1;
}
}
if ((ret = ff_get_buffer(avctx, frame, AV_GET_BUFFER_FLAG_REF)) < 0) {
av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
return ret;
}
new_frame_data = (uint16_t*)frame->data[0];
new_stride = 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);
av_frame_unref(s->frame);
if ((ret = av_frame_ref(s->frame, frame)) < 0)
return ret;
*got_frame = 1;
return frame_size;
}