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DEFINITIONS
This source file includes following definitions.
- tgv_decode_init
- unpack
- tgv_decode_inter
- cond_release_buffer
- tgv_decode_frame
- tgv_decode_end
/*
* Electronic Arts TGV Video Decoder
* Copyright (c) 2007-2008 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 St, Fifth Floor, Boston, MA 02110-1301 USA
*/
/**
* @file libavcodec/eatgv.c
* Electronic Arts TGV Video Decoder
* by Peter Ross (suxen_drol at hotmail dot com)
*
* Technical details here:
* http://wiki.multimedia.cx/index.php?title=Electronic_Arts_TGV
*/
#include "avcodec.h"
#define ALT_BITSTREAM_READER_LE
#include "bitstream.h"
#include "libavutil/lzo.h"
#define EA_PREAMBLE_SIZE 8
#define kVGT_TAG MKTAG('k', 'V', 'G', 'T')
typedef struct TgvContext {
AVCodecContext *avctx;
AVFrame frame;
AVFrame last_frame;
int width,height;
unsigned int palette[AVPALETTE_COUNT];
int (*mv_codebook)[2];
unsigned char (*block_codebook)[16];
int num_mvs; ///< current length of mv_codebook
int num_blocks_packed; ///< current length of block_codebook
} TgvContext;
static av_cold int tgv_decode_init(AVCodecContext *avctx){
TgvContext *s = avctx->priv_data;
s->avctx = avctx;
avctx->time_base = (AVRational){1, 15};
avctx->pix_fmt = PIX_FMT_PAL8;
return 0;
}
/**
* Unpack buffer
* @return 0 on success, -1 on critical buffer underflow
*/
static int unpack(const uint8_t *src, const uint8_t *src_end, unsigned char *dst, int width, int height) {
unsigned char *dst_end = dst + width*height;
int size, size1, size2, av_uninit(offset), run;
unsigned char *dst_start = dst;
if (src[0] & 0x01)
src += 5;
else
src += 2;
if (src+3>src_end)
return -1;
size = AV_RB24(src);
src += 3;
while(size>0 && src<src_end) {
/* determine size1 and size2 */
size1 = (src[0] & 3);
if ( src[0] & 0x80 ) { // 1
if (src[0] & 0x40 ) { // 11
if ( src[0] & 0x20 ) { // 111
if ( src[0] < 0xFC ) // !(111111)
size1 = (((src[0] & 31) + 1) << 2);
src++;
size2 = 0;
} else { // 110
offset = ((src[0] & 0x10) << 12) + AV_RB16(&src[1]) + 1;
size2 = ((src[0] & 0xC) << 6) + src[3] + 5;
src += 4;
}
} else { // 10
size1 = ( ( src[1] & 0xC0) >> 6 );
offset = (AV_RB16(&src[1]) & 0x3FFF) + 1;
size2 = (src[0] & 0x3F) + 4;
src += 3;
}
} else { // 0
offset = ((src[0] & 0x60) << 3) + src[1] + 1;
size2 = ((src[0] & 0x1C) >> 2) + 3;
src += 2;
}
/* fetch strip from src */
if (size1>src_end-src)
break;
if (size1>0) {
size -= size1;
run = FFMIN(size1, dst_end-dst);
memcpy(dst, src, run);
dst += run;
src += run;
}
if (size2>0) {
if (dst-dst_start<offset)
return 0;
size -= size2;
run = FFMIN(size2, dst_end-dst);
av_memcpy_backptr(dst, offset, run);
dst += run;
}
}
return 0;
}
/**
* Decode inter-frame
* @return 0 on success, -1 on critical buffer underflow
*/
static int tgv_decode_inter(TgvContext * s, const uint8_t *buf, const uint8_t *buf_end){
unsigned char *frame0_end = s->last_frame.data[0] + s->avctx->width*s->last_frame.linesize[0];
int num_mvs;
int num_blocks_raw;
int num_blocks_packed;
int vector_bits;
int i,j,x,y;
GetBitContext gb;
int mvbits;
const unsigned char *blocks_raw;
if(buf+12>buf_end)
return -1;
num_mvs = AV_RL16(&buf[0]);
num_blocks_raw = AV_RL16(&buf[2]);
num_blocks_packed = AV_RL16(&buf[4]);
vector_bits = AV_RL16(&buf[6]);
buf += 12;
/* allocate codebook buffers as neccessary */
if (num_mvs > s->num_mvs) {
s->mv_codebook = av_realloc(s->mv_codebook, num_mvs*2*sizeof(int));
s->num_mvs = num_mvs;
}
if (num_blocks_packed > s->num_blocks_packed) {
s->block_codebook = av_realloc(s->block_codebook, num_blocks_packed*16*sizeof(unsigned char));
s->num_blocks_packed = num_blocks_packed;
}
/* read motion vectors */
mvbits = (num_mvs*2*10+31) & ~31;
if (buf+(mvbits>>3)+16*num_blocks_raw+8*num_blocks_packed>buf_end)
return -1;
init_get_bits(&gb, buf, mvbits);
for (i=0; i<num_mvs; i++) {
s->mv_codebook[i][0] = get_sbits(&gb, 10);
s->mv_codebook[i][1] = get_sbits(&gb, 10);
}
buf += mvbits>>3;
/* note ptr to uncompressed blocks */
blocks_raw = buf;
buf += num_blocks_raw*16;
/* read compressed blocks */
init_get_bits(&gb, buf, (buf_end-buf)<<3);
for (i=0; i<num_blocks_packed; i++) {
int tmp[4];
for(j=0; j<4; j++)
tmp[j] = get_bits(&gb, 8);
for(j=0; j<16; j++)
s->block_codebook[i][15-j] = tmp[get_bits(&gb, 2)];
}
/* read vectors and build frame */
for(y=0; y<s->avctx->height/4; y++)
for(x=0; x<s->avctx->width/4; x++) {
unsigned int vector = get_bits(&gb, vector_bits);
const unsigned char *src;
int src_stride;
if (vector < num_mvs) {
src = s->last_frame.data[0] +
(y*4 + s->mv_codebook[vector][1])*s->last_frame.linesize[0] +
x*4 + s->mv_codebook[vector][0];
src_stride = s->last_frame.linesize[0];
if (src+3*src_stride+3>=frame0_end)
continue;
}else{
int offset = vector - num_mvs;
if (offset<num_blocks_raw)
src = blocks_raw + 16*offset;
else if (offset-num_blocks_raw<num_blocks_packed)
src = s->block_codebook[offset-num_blocks_raw];
else
continue;
src_stride = 4;
}
for(j=0; j<4; j++)
for(i=0; i<4; i++)
s->frame.data[0][ (y*4+j)*s->frame.linesize[0] + (x*4+i) ] =
src[j*src_stride + i];
}
return 0;
}
/** release AVFrame buffers if allocated */
static void cond_release_buffer(AVFrame *pic)
{
if (pic->data[0]) {
av_freep(&pic->data[0]);
av_free(pic->data[1]);
}
}
static int tgv_decode_frame(AVCodecContext *avctx,
void *data, int *data_size,
const uint8_t *buf, int buf_size)
{
TgvContext *s = avctx->priv_data;
const uint8_t *buf_end = buf + buf_size;
int chunk_type;
chunk_type = AV_RL32(&buf[0]);
buf += EA_PREAMBLE_SIZE;
if (chunk_type==kVGT_TAG) {
int pal_count, i;
if(buf+12>buf_end) {
av_log(avctx, AV_LOG_WARNING, "truncated header\n");
return -1;
}
s->width = AV_RL16(&buf[0]);
s->height = AV_RL16(&buf[2]);
if (s->avctx->width!=s->width || s->avctx->height!=s->height) {
avcodec_set_dimensions(s->avctx, s->width, s->height);
cond_release_buffer(&s->frame);
cond_release_buffer(&s->last_frame);
}
pal_count = AV_RL16(&buf[6]);
buf += 12;
for(i=0; i<pal_count && i<AVPALETTE_COUNT && buf+2<buf_end; i++) {
s->palette[i] = AV_RB24(buf);
buf += 3;
}
}
if (avcodec_check_dimensions(avctx, s->width, s->height))
return -1;
/* shuffle */
FFSWAP(AVFrame, s->frame, s->last_frame);
if (!s->frame.data[0]) {
s->frame.reference = 1;
s->frame.buffer_hints = FF_BUFFER_HINTS_VALID;
s->frame.linesize[0] = s->width;
/* allocate additional 12 bytes to accomodate av_memcpy_backptr() OUTBUF_PADDED optimisation */
s->frame.data[0] = av_malloc(s->width*s->height + 12);
if (!s->frame.data[0])
return AVERROR_NOMEM;
s->frame.data[1] = av_malloc(AVPALETTE_SIZE);
if (!s->frame.data[1]) {
av_freep(&s->frame.data[0]);
return AVERROR_NOMEM;
}
}
memcpy(s->frame.data[1], s->palette, AVPALETTE_SIZE);
if(chunk_type==kVGT_TAG) {
s->frame.key_frame = 1;
s->frame.pict_type = FF_I_TYPE;
if (unpack(buf, buf_end, s->frame.data[0], s->avctx->width, s->avctx->height)<0) {
av_log(avctx, AV_LOG_WARNING, "truncated intra frame\n");
return -1;
}
}else{
if (!s->last_frame.data[0]) {
av_log(avctx, AV_LOG_WARNING, "inter frame without corresponding intra frame\n");
return buf_size;
}
s->frame.key_frame = 0;
s->frame.pict_type = FF_P_TYPE;
if (tgv_decode_inter(s, buf, buf_end)<0) {
av_log(avctx, AV_LOG_WARNING, "truncated inter frame\n");
return -1;
}
}
*data_size = sizeof(AVFrame);
*(AVFrame*)data = s->frame;
return buf_size;
}
static av_cold int tgv_decode_end(AVCodecContext *avctx)
{
TgvContext *s = avctx->priv_data;
cond_release_buffer(&s->frame);
cond_release_buffer(&s->last_frame);
av_free(s->mv_codebook);
av_free(s->block_codebook);
return 0;
}
AVCodec eatgv_decoder = {
"eatgv",
CODEC_TYPE_VIDEO,
CODEC_ID_TGV,
sizeof(TgvContext),
tgv_decode_init,
NULL,
tgv_decode_end,
tgv_decode_frame,
.long_name = NULL_IF_CONFIG_SMALL("Electronic Arts TGV video"),
};