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FFmpeg/libavcodec/mimic.c

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/*
* Copyright (C) 2005 Ole André Vadla Ravnås <oleavr@gmail.com>
* Copyright (C) 2008 Ramiro Polla <ramiro@lisha.ufsc.br>
*
* 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 <stdlib.h>
#include <string.h>
#include <stdint.h>
#include "avcodec.h"
#include "get_bits.h"
#include "bytestream.h"
#include "dsputil.h"
#define MIMIC_HEADER_SIZE 20
typedef struct {
AVCodecContext *avctx;
int num_vblocks[3];
int num_hblocks[3];
void *swap_buf;
int swap_buf_size;
int cur_index;
int prev_index;
AVFrame buf_ptrs [16];
AVPicture flipped_ptrs[16];
DECLARE_ALIGNED_16(DCTELEM, dct_block[64]);
GetBitContext gb;
ScanTable scantable;
DSPContext dsp;
VLC vlc;
} MimicContext;
static const uint32_t huffcodes[] = {
0x0000000a, 0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000,
0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000,
0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x0000000b,
0x0000001b, 0x00000038, 0x00000078, 0x00000079, 0x0000007a, 0x000000f9,
0x000000fa, 0x000003fb, 0x000007f8, 0x000007f9, 0x000007fa, 0x000007fb,
0x00000ff8, 0x00000ff9, 0x00000001, 0x00000039, 0x0000007b, 0x000000fb,
0x000001f8, 0x000001f9, 0x00000ffa, 0x00000ffb, 0x00001ff8, 0x00001ff9,
0x00001ffa, 0x00001ffb, 0x00003ff8, 0x00003ff9, 0x00003ffa, 0x00000000,
0x00000004, 0x0000003a, 0x000001fa, 0x00003ffb, 0x00007ff8, 0x00007ff9,
0x00007ffa, 0x00007ffb, 0x0000fff8, 0x0000fff9, 0x0000fffa, 0x0000fffb,
0x0001fff8, 0x0001fff9, 0x0001fffa, 0x00000000, 0x0000000c, 0x000000f8,
0x000001fb, 0x0001fffb, 0x0003fff8, 0x0003fff9, 0x0003fffa, 0x0003fffb,
0x0007fff8, 0x0007fff9, 0x0007fffa, 0x0007fffb, 0x000ffff8, 0x000ffff9,
0x000ffffa, 0x00000000, 0x0000001a, 0x000003f8, 0x000ffffb, 0x001ffff8,
0x001ffff9, 0x001ffffa, 0x001ffffb, 0x003ffff8, 0x003ffff9, 0x003ffffa,
0x003ffffb, 0x007ffff8, 0x007ffff9, 0x007ffffa, 0x007ffffb, 0x00000000,
0x0000003b, 0x000003f9, 0x00fffff8, 0x00fffff9, 0x00fffffa, 0x00fffffb,
0x01fffff8, 0x01fffff9, 0x01fffffa, 0x01fffffb, 0x03fffff8, 0x03fffff9,
0x03fffffa, 0x03fffffb, 0x07fffff8, 0x00000000, 0x000003fa, 0x07fffff9,
0x07fffffa, 0x07fffffb, 0x0ffffff8, 0x0ffffff9, 0x0ffffffa, 0x0ffffffb,
0x1ffffff8, 0x1ffffff9, 0x1ffffffa, 0x1ffffffb, 0x3ffffff8, 0x3ffffff9,
0x3ffffffa,
};
static const uint8_t huffbits[] = {
4, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 2, 4, 5, 6, 7, 7, 7, 8,
8, 10, 11, 11, 11, 11, 12, 12, 2, 6, 7, 8,
9, 9, 12, 12, 13, 13, 13, 13, 14, 14, 14, 0,
3, 6, 9, 14, 15, 15, 15, 15, 16, 16, 16, 16,
17, 17, 17, 0, 4, 8, 9, 17, 18, 18, 18, 18,
19, 19, 19, 19, 20, 20, 20, 0, 5, 10, 20, 21,
21, 21, 21, 22, 22, 22, 22, 23, 23, 23, 23, 0,
6, 10, 24, 24, 24, 24, 25, 25, 25, 25, 26, 26,
26, 26, 27, 0, 10, 27, 27, 27, 28, 28, 28, 28,
29, 29, 29, 29, 30, 30, 30,
};
static const uint8_t col_zag[64] = {
0, 8, 1, 2, 9, 16, 24, 17,
10, 3, 4, 11, 18, 25, 32, 40,
33, 26, 19, 12, 5, 6, 13, 20,
27, 34, 41, 48, 56, 49, 42, 35,
28, 21, 14, 7, 15, 22, 29, 36,
43, 50, 57, 58, 51, 44, 37, 30,
23, 31, 38, 45, 52, 59, 39, 46,
53, 60, 61, 54, 47, 55, 62, 63,
};
static av_cold int mimic_decode_init(AVCodecContext *avctx)
{
MimicContext *ctx = avctx->priv_data;
ctx->prev_index = 0;
ctx->cur_index = 15;
if(init_vlc(&ctx->vlc, 11, FF_ARRAY_ELEMS(huffbits),
huffbits, 1, 1, huffcodes, 4, 4, 0)) {
av_log(avctx, AV_LOG_ERROR, "error initializing vlc table\n");
return -1;
}
dsputil_init(&ctx->dsp, avctx);
ff_init_scantable(ctx->dsp.idct_permutation, &ctx->scantable, col_zag);
return 0;
}
static const int8_t vlcdec_lookup[9][64] = {
{ 0, },
{ -1, 1, },
{ -3, 3, -2, 2, },
{ -7, 7, -6, 6, -5, 5, -4, 4, },
{ -15, 15, -14, 14, -13, 13, -12, 12,
-11, 11, -10, 10, -9, 9, -8, 8, },
{ -31, 31, -30, 30, -29, 29, -28, 28,
-27, 27, -26, 26, -25, 25, -24, 24,
-23, 23, -22, 22, -21, 21, -20, 20,
-19, 19, -18, 18, -17, 17, -16, 16, },
{ -63, 63, -62, 62, -61, 61, -60, 60,
-59, 59, -58, 58, -57, 57, -56, 56,
-55, 55, -54, 54, -53, 53, -52, 52,
-51, 51, -50, 50, -49, 49, -48, 48,
-47, 47, -46, 46, -45, 45, -44, 44,
-43, 43, -42, 42, -41, 41, -40, 40,
-39, 39, -38, 38, -37, 37, -36, 36,
-35, 35, -34, 34, -33, 33, -32, 32, },
{ -127, 127, -126, 126, -125, 125, -124, 124,
-123, 123, -122, 122, -121, 121, -120, 120,
-119, 119, -118, 118, -117, 117, -116, 116,
-115, 115, -114, 114, -113, 113, -112, 112,
-111, 111, -110, 110, -109, 109, -108, 108,
-107, 107, -106, 106, -105, 105, -104, 104,
-103, 103, -102, 102, -101, 101, -100, 100,
-99, 99, -98, 98, -97, 97, -96, 96, },
{ -95, 95, -94, 94, -93, 93, -92, 92,
-91, 91, -90, 90, -89, 89, -88, 88,
-87, 87, -86, 86, -85, 85, -84, 84,
-83, 83, -82, 82, -81, 81, -80, 80,
-79, 79, -78, 78, -77, 77, -76, 76,
-75, 75, -74, 74, -73, 73, -72, 72,
-71, 71, -70, 70, -69, 69, -68, 68,
-67, 67, -66, 66, -65, 65, -64, 64, },
};
static int vlc_decode_block(MimicContext *ctx, int num_coeffs, int qscale)
{
DCTELEM *block = ctx->dct_block;
unsigned int pos;
ctx->dsp.clear_block(block);
block[0] = get_bits(&ctx->gb, 8) << 3;
for(pos = 1; pos < num_coeffs; pos++) {
uint32_t vlc, num_bits;
int value;
int coeff;
vlc = get_vlc2(&ctx->gb, ctx->vlc.table, ctx->vlc.bits, 3);
if(!vlc) /* end-of-block code */
return 1;
if(vlc == -1)
return 0;
/* pos_add and num_bits are coded in the vlc code */
pos += vlc&15; // pos_add
num_bits = vlc>>4; // num_bits
if(pos >= 64)
return 0;
value = get_bits(&ctx->gb, num_bits);
/* FFmpeg's IDCT behaves somewhat different from the original code, so
* a factor of 4 was added to the input */
coeff = vlcdec_lookup[num_bits][value];
if(pos<3)
coeff <<= 4;
else /* TODO Use >> 10 instead of / 1001 */
coeff = (coeff * qscale) / 1001;
block[ctx->scantable.permutated[pos]] = coeff;
}
return 1;
}
static int decode(MimicContext *ctx, int quality, int num_coeffs,
int is_iframe)
{
int y, x, plane;
for(plane = 0; plane < 3; plane++) {
const int is_chroma = !!plane;
const int qscale = av_clip(10000-quality,is_chroma?1000:2000,10000)<<2;
const int stride = ctx->flipped_ptrs[ctx->cur_index].linesize[plane];
const uint8_t *src = ctx->flipped_ptrs[ctx->prev_index].data[plane];
uint8_t *dst = ctx->flipped_ptrs[ctx->cur_index ].data[plane];
for(y = 0; y < ctx->num_vblocks[plane]; y++) {
for(x = 0; x < ctx->num_hblocks[plane]; x++) {
/* Check for a change condition in the current block.
* - iframes always change.
* - Luma plane changes on get_bits1 == 0
* - Chroma planes change on get_bits1 == 1 */
if(is_iframe || get_bits1(&ctx->gb) == is_chroma) {
/* Luma planes may use a backreference from the 15 last
* frames preceding the previous. (get_bits1 == 1)
* Chroma planes don't use backreferences. */
if(is_chroma || is_iframe || !get_bits1(&ctx->gb)) {
if(!vlc_decode_block(ctx, num_coeffs, qscale))
return 0;
ctx->dsp.idct_put(dst, stride, ctx->dct_block);
} else {
unsigned int backref = get_bits(&ctx->gb, 4);
int index = (ctx->cur_index+backref)&15;
uint8_t *p = ctx->flipped_ptrs[index].data[0];
if(p) {
p += src -
ctx->flipped_ptrs[ctx->prev_index].data[plane];
ctx->dsp.put_pixels_tab[1][0](dst, p, stride, 8);
} else {
av_log(ctx->avctx, AV_LOG_ERROR,
"No such backreference! Buggy sample.\n");
}
}
} else {
ctx->dsp.put_pixels_tab[1][0](dst, src, stride, 8);
}
src += 8;
dst += 8;
}
src += (stride - ctx->num_hblocks[plane])<<3;
dst += (stride - ctx->num_hblocks[plane])<<3;
}
}
return 1;
}
/**
* Flip the buffer upside-down and put it in the YVU order to match the
* way Mimic encodes frames.
*/
static void prepare_avpic(MimicContext *ctx, AVPicture *dst, AVPicture *src)
{
int i;
dst->data[0] = src->data[0]+( ctx->avctx->height -1)*src->linesize[0];
dst->data[1] = src->data[2]+((ctx->avctx->height>>1)-1)*src->linesize[2];
dst->data[2] = src->data[1]+((ctx->avctx->height>>1)-1)*src->linesize[1];
for(i = 0; i < 3; i++)
dst->linesize[i] = -src->linesize[i];
}
static int mimic_decode_frame(AVCodecContext *avctx, void *data,
int *data_size, AVPacket *avpkt)
{
const uint8_t *buf = avpkt->data;
int buf_size = avpkt->size;
MimicContext *ctx = avctx->priv_data;
int is_pframe;
int width, height;
int quality, num_coeffs;
int swap_buf_size = buf_size - MIMIC_HEADER_SIZE;
if(buf_size < MIMIC_HEADER_SIZE) {
av_log(avctx, AV_LOG_ERROR, "insufficient data\n");
return -1;
}
buf += 2; /* some constant (always 256) */
quality = bytestream_get_le16(&buf);
width = bytestream_get_le16(&buf);
height = bytestream_get_le16(&buf);
buf += 4; /* some constant */
is_pframe = bytestream_get_le32(&buf);
num_coeffs = bytestream_get_byte(&buf);
buf += 3; /* some constant */
if(!ctx->avctx) {
int i;
if(!(width == 160 && height == 120) &&
!(width == 320 && height == 240)) {
av_log(avctx, AV_LOG_ERROR, "invalid width/height!\n");
return -1;
}
ctx->avctx = avctx;
avctx->width = width;
avctx->height = height;
avctx->pix_fmt = PIX_FMT_YUV420P;
for(i = 0; i < 3; i++) {
ctx->num_vblocks[i] = -((-height) >> (3 + !!i));
ctx->num_hblocks[i] = width >> (3 + !!i) ;
}
} else if(width != ctx->avctx->width || height != ctx->avctx->height) {
av_log(avctx, AV_LOG_ERROR, "resolution changing is not supported\n");
return -1;
}
if(is_pframe && !ctx->buf_ptrs[ctx->prev_index].data[0]) {
av_log(avctx, AV_LOG_ERROR, "decoding must start with keyframe\n");
return -1;
}
ctx->buf_ptrs[ctx->cur_index].reference = 1;
if(avctx->get_buffer(avctx, &ctx->buf_ptrs[ctx->cur_index])) {
av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
return -1;
}
prepare_avpic(ctx, &ctx->flipped_ptrs[ctx->cur_index],
(AVPicture*) &ctx->buf_ptrs[ctx->cur_index]);
av_fast_malloc(&ctx->swap_buf, &ctx->swap_buf_size,
swap_buf_size + FF_INPUT_BUFFER_PADDING_SIZE);
if(!ctx->swap_buf)
return AVERROR(ENOMEM);
ctx->dsp.bswap_buf(ctx->swap_buf,
(const uint32_t*) buf,
swap_buf_size>>2);
init_get_bits(&ctx->gb, ctx->swap_buf, swap_buf_size << 3);
if(!decode(ctx, quality, num_coeffs, !is_pframe)) {
avctx->release_buffer(avctx, &ctx->buf_ptrs[ctx->cur_index]);
return -1;
}
ctx->buf_ptrs[ctx->cur_index].pict_type = is_pframe ? FF_P_TYPE:FF_I_TYPE;
*(AVFrame*)data = ctx->buf_ptrs[ctx->cur_index];
*data_size = sizeof(AVFrame);
ctx->prev_index = ctx->cur_index;
ctx->cur_index--;
ctx->cur_index &= 15;
/* Only release frames that aren't used for backreferences anymore */
if(ctx->buf_ptrs[ctx->cur_index].data[0])
avctx->release_buffer(avctx, &ctx->buf_ptrs[ctx->cur_index]);
return buf_size;
}
static av_cold int mimic_decode_end(AVCodecContext *avctx)
{
MimicContext *ctx = avctx->priv_data;
int i;
av_free(ctx->swap_buf);
for(i = 0; i < 16; i++)
if(ctx->buf_ptrs[i].data[0])
avctx->release_buffer(avctx, &ctx->buf_ptrs[i]);
free_vlc(&ctx->vlc);
return 0;
}
AVCodec mimic_decoder = {
"mimic",
CODEC_TYPE_VIDEO,
CODEC_ID_MIMIC,
sizeof(MimicContext),
mimic_decode_init,
NULL,
mimic_decode_end,
mimic_decode_frame,
CODEC_CAP_DR1,
.long_name = NULL_IF_CONFIG_SMALL("Mimic"),
};