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Lagarith decoder by Nathan Caldwell, saintdev at gmail

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Originally committed as revision 26270 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Carl Eugen Hoyos 2011-01-08 21:22:15 +00:00
parent c392cc0a64
commit d267b339e4
9 changed files with 699 additions and 1 deletions
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1
Changelog
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@ -71,6 +71,7 @@ version <next>:
- FFmpeg metadata format muxer and demuxer
- SubRip (srt) subtitle decoder
- floating-point AC-3 encoder added
- Lagarith decoder
version 0.6:

1
doc/general.texi
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@ -424,6 +424,7 @@ following image formats are supported:
@tab Codec used in Worms games.
@item Kega Game Video (KGV1) @tab @tab X
@tab Kega emulator screen capture codec.
@item Lagarith @tab @tab X
@item LCL (LossLess Codec Library) MSZH @tab @tab X
@item LCL (LossLess Codec Library) ZLIB @tab E @tab E
@item LOCO @tab @tab X

1
libavcodec/Makefile
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@ -185,6 +185,7 @@ OBJS-$(CONFIG_JPEGLS_DECODER) += jpeglsdec.o jpegls.o \
OBJS-$(CONFIG_JPEGLS_ENCODER) += jpeglsenc.o jpegls.o
OBJS-$(CONFIG_KGV1_DECODER) += kgv1dec.o
OBJS-$(CONFIG_KMVC_DECODER) += kmvc.o
OBJS-$(CONFIG_LAGARITH_DECODER) += lagarith.o lagarithrac.o
OBJS-$(CONFIG_LJPEG_ENCODER) += ljpegenc.o mjpegenc.o mjpeg.o \
mpegvideo_enc.o motion_est.o \
ratecontrol.o mpeg12data.o \

1
libavcodec/allcodecs.c
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@ -128,6 +128,7 @@ void avcodec_register_all(void)
REGISTER_ENCDEC (JPEGLS, jpegls);
REGISTER_DECODER (KGV1, kgv1);
REGISTER_DECODER (KMVC, kmvc);
REGISTER_DECODER (LAGARITH, lagarith);
REGISTER_ENCODER (LJPEG, ljpeg);
REGISTER_DECODER (LOCO, loco);
REGISTER_DECODER (MDEC, mdec);

3
libavcodec/avcodec.h
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@ -32,7 +32,7 @@
#include "libavutil/cpu.h"
#define LIBAVCODEC_VERSION_MAJOR 52
#define LIBAVCODEC_VERSION_MINOR 107
#define LIBAVCODEC_VERSION_MINOR 108
#define LIBAVCODEC_VERSION_MICRO 0
#define LIBAVCODEC_VERSION_INT AV_VERSION_INT(LIBAVCODEC_VERSION_MAJOR, \
@ -259,6 +259,7 @@ enum CodecID {
CODEC_ID_A64_MULTI5,
CODEC_ID_R10K,
CODEC_ID_MXPEG,
CODEC_ID_LAGARITH,
/* various PCM "codecs" */
CODEC_ID_PCM_S16LE= 0x10000,

518
libavcodec/lagarith.c Normal file
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@ -0,0 +1,518 @@
/*
* Lagarith lossless decoder
* Copyright (c) 2009 Nathan Caldwell <saintdev (at) 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
*/
/**
* @file libavcodec/lagarith.c
* Lagarith lossless decoder
* @author Nathan Caldwell
*/
#include "avcodec.h"
#include "get_bits.h"
#include "mathops.h"
#include "dsputil.h"
#include "lagarithrac.h"
enum LagarithFrameType {
FRAME_RAW = 1, /*!< uncompressed */
FRAME_U_RGB24 = 2, /*!< unaligned RGB24 */
FRAME_ARITH_YUY2 = 3, /*!< arithmetic coded YUY2 */
FRAME_ARITH_RGB24 = 4, /*!< arithmetic coded RGB24 */
FRAME_SOLID_GRAY = 5, /*!< solid grayscale color frame */
FRAME_SOLID_COLOR = 6, /*!< solid non-grayscale color frame */
FRAME_OLD_ARITH_RGB = 7, /*!< obsolete arithmetic coded RGB (no longer encoded by upstream since version 1.1.0) */
FRAME_ARITH_RGBA = 8, /*!< arithmetic coded RGBA */
FRAME_SOLID_RGBA = 9, /*!< solid RGBA color frame */
FRAME_ARITH_YV12 = 10, /*!< arithmetic coded YV12 */
FRAME_REDUCED_RES = 11, /*!< reduced resolution YV12 frame */
};
typedef struct LagarithContext {
AVCodecContext *avctx;
AVFrame picture;
DSPContext dsp;
int zeros; /*!< number of consecutive zero bytes encountered */
int zeros_rem; /*!< number of zero bytes remaining to output */
} LagarithContext;
/**
* Compute the 52bit mantissa of 1/(double)denom.
* This crazy format uses floats in an entropy coder and we have to match x86
* rounding exactly, thus ordinary floats aren't portable enough.
* @param denom denominator
* @return 52bit mantissa
* @see softfloat_mul
*/
static uint64_t softfloat_reciprocal(uint32_t denom)
{
int shift = av_log2(denom - 1) + 1;
uint64_t ret = (1ULL << 52) / denom;
uint64_t err = (1ULL << 52) - ret * denom;
ret <<= shift;
err <<= shift;
err += denom / 2;
return ret + err / denom;
}
/**
* (uint32_t)(x*f), where f has the given mantissa, and exponent 0
* Used in combination with softfloat_reciprocal computes x/(double)denom.
* @param x 32bit integer factor
* @param mantissa mantissa of f with exponent 0
* @return 32bit integer value (x*f)
* @see softfloat_reciprocal
*/
static uint32_t softfloat_mul(uint32_t x, uint64_t mantissa)
{
uint64_t l = x * (mantissa & 0xffffffff);
uint64_t h = x * (mantissa >> 32);
h += l >> 32;
l &= 0xffffffff;
l += 1 << av_log2(h >> 21);
h += l >> 32;
return h >> 20;
}
static uint8_t lag_calc_zero_run(int8_t x)
{
return (x << 1) ^ (x >> 7);
}
static int lag_decode_prob(GetBitContext *gb, uint32_t *value)
{
static const uint8_t series[] = { 1, 2, 3, 5, 8, 13, 21 };
int i;
int bit = 0;
int bits = 0;
int prevbit = 0;
unsigned val;
for (i = 0; i < 7; i++) {
if (prevbit && bit)
break;
prevbit = bit;
bit = get_bits1(gb);
if (bit && !prevbit)
bits += series[i];
}
bits--;
if (bits < 0 || bits > 31) {
*value = 0;
return -1;
} else if (bits == 0) {
*value = 0;
return 0;
}
val = get_bits_long(gb, bits);
val |= 1 << bits;
*value = val - 1;
return 0;
}
static int lag_read_prob_header(lag_rac *rac, GetBitContext *gb)
{
int i, j, scale_factor;
unsigned prob, cumulative_target;
unsigned cumul_prob = 0;
unsigned scaled_cumul_prob = 0;
rac->prob[0] = 0;
rac->prob[257] = UINT_MAX;
/* Read probabilities from bitstream */
for (i = 1; i < 257; i++) {
if (lag_decode_prob(gb, &rac->prob[i]) < 0) {
av_log(rac->avctx, AV_LOG_ERROR, "Invalid probability encountered.\n");
return -1;
}
if ((uint64_t)cumul_prob + rac->prob[i] > UINT_MAX) {
av_log(rac->avctx, AV_LOG_ERROR, "Integer overflow encountered in cumulative probability calculation.\n");
return -1;
}
cumul_prob += rac->prob[i];
if (!rac->prob[i]) {
if (lag_decode_prob(gb, &prob)) {
av_log(rac->avctx, AV_LOG_ERROR, "Invalid probability run encountered.\n");
return -1;
}
if (prob > 257 - i)
prob = 257 - i;
for (j = 0; j < prob; j++)
rac->prob[++i] = 0;
}
}
if (!cumul_prob) {
av_log(rac->avctx, AV_LOG_ERROR, "All probabilities are 0!\n");
return -1;
}
/* Scale probabilities so cumulative probability is an even power of 2. */
scale_factor = av_log2(cumul_prob);
if (cumul_prob & (cumul_prob - 1)) {
uint64_t mul = softfloat_reciprocal(cumul_prob);
for (i = 1; i < 257; i++) {
rac->prob[i] = softfloat_mul(rac->prob[i], mul);
scaled_cumul_prob += rac->prob[i];
}
scale_factor++;
cumulative_target = 1 << scale_factor;
if (scaled_cumul_prob > cumulative_target) {
av_log(rac->avctx, AV_LOG_ERROR,
"Scaled probabilities are larger than target!\n");
return -1;
}
scaled_cumul_prob = cumulative_target - scaled_cumul_prob;
for (i = 1; scaled_cumul_prob; i = (i & 0x7f) + 1) {
if (rac->prob[i]) {
rac->prob[i]++;
scaled_cumul_prob--;
}
/* Comment from reference source:
* if (b & 0x80 == 0) { // order of operations is 'wrong'; it has been left this way
* // since the compression change is negligable and fixing it
* // breaks backwards compatibilty
* b =- (signed int)b;
* b &= 0xFF;
* } else {
* b++;
* b &= 0x7f;
* }
*/
}
}
rac->scale = scale_factor;
/* Fill probability array with cumulative probability for each symbol. */
for (i = 1; i < 257; i++)
rac->prob[i] += rac->prob[i - 1];
return 0;
}
static void add_lag_median_prediction(uint8_t *dst, uint8_t *src1,
uint8_t *diff, int w, int *left,
int *left_top)
{
/* This is almost identical to add_hfyu_median_prediction in dsputil.h.
* However the &0xFF on the gradient predictor yealds incorrect output
* for lagarith.
*/
int i;
uint8_t l, lt;
l = *left;
lt = *left_top;
for (i = 0; i < w; i++) {
l = mid_pred(l, src1[i], l + src1[i] - lt) + diff[i];
lt = src1[i];
dst[i] = l;
}
*left = l;
*left_top = lt;
}
static void lag_pred_line(LagarithContext *l, uint8_t *buf,
int width, int stride, int line)
{
int L, TL;
if (!line) {
/* Left prediction only for first line */
L = l->dsp.add_hfyu_left_prediction(buf + 1, buf + 1,
width - 1, buf[0]);
return;
} else if (line == 1) {
/* Second line, left predict first pixel, the rest of the line is median predicted */
/* FIXME: In the case of RGB this pixel is top predicted */
TL = buf[-stride];
} else {
/* Top left is 2 rows back, last pixel */
TL = buf[width - (2 * stride) - 1];
}
/* Left pixel is actually prev_row[width] */
L = buf[width - stride - 1];
add_lag_median_prediction(buf, buf - stride, buf,
width, &L, &TL);
}
static int lag_decode_line(LagarithContext *l, lag_rac *rac,
uint8_t *dst, int width, int stride,
int esc_count)
{
int i = 0;
int ret = 0;
if (!esc_count)
esc_count = -1;
/* Output any zeros remaining from the previous run */
handle_zeros:
if (l->zeros_rem) {
int count = FFMIN(l->zeros_rem, width - i);
memset(dst + i, 0, count);
i += count;
l->zeros_rem -= count;
}
while (i < width) {
dst[i] = lag_get_rac(rac);
ret++;
if (dst[i])
l->zeros = 0;
else
l->zeros++;
i++;
if (l->zeros == esc_count) {
int index = lag_get_rac(rac);
ret++;
l->zeros = 0;
l->zeros_rem = lag_calc_zero_run(index);
goto handle_zeros;
}
}
return ret;
}
static int lag_decode_zero_run_line(LagarithContext *l, uint8_t *dst,
const uint8_t *src, int width,
int esc_count)
{
int i = 0;
int count;
uint8_t zero_run = 0;
const uint8_t *start = src;
uint8_t mask1 = -(esc_count < 2);
uint8_t mask2 = -(esc_count < 3);
uint8_t *end = dst + (width - 2);
output_zeros:
if (l->zeros_rem) {
count = FFMIN(l->zeros_rem, width - i);
memset(dst, 0, count);
l->zeros_rem -= count;
dst += count;
}
while (dst < end) {
i = 0;
while (!zero_run && dst + i < end) {
i++;
zero_run =
!(src[i] | (src[i + 1] & mask1) | (src[i + 2] & mask2));
}
if (zero_run) {
zero_run = 0;
i += esc_count;
memcpy(dst, src, i);
dst += i;
l->zeros_rem = lag_calc_zero_run(src[i]);
src += i + 1;
goto output_zeros;
} else {
memcpy(dst, src, i);
src += i;
}
}
return start - src;
}
static int lag_decode_arith_plane(LagarithContext *l, uint8_t *dst,
int width, int height, int stride,
const uint8_t *src, int src_size)
{
int i = 0;
int read = 0;
uint32_t length;
uint32_t offset = 1;
int esc_count = src[0];
GetBitContext gb;
lag_rac rac;
rac.avctx = l->avctx;
l->zeros = 0;
if (esc_count < 4) {
length = width * height;
if (esc_count && AV_RL32(src + 1) < length) {
length = AV_RL32(src + 1);
offset += 4;
}
init_get_bits(&gb, src + offset, src_size * 8);
if (lag_read_prob_header(&rac, &gb) < 0)
return -1;
lag_rac_init(&rac, &gb, length - stride);
for (i = 0; i < height; i++)
read += lag_decode_line(l, &rac, dst + (i * stride), width,
stride, esc_count);
if (read > length)
av_log(l->avctx, AV_LOG_WARNING,
"Output more bytes than length (%d of %d)\n", read,
length);
} else if (esc_count < 8) {
esc_count -= 4;
if (esc_count > 0) {
/* Zero run coding only, no range coding. */
for (i = 0; i < height; i++)
src += lag_decode_zero_run_line(l, dst + (i * stride), src,
width, esc_count);
} else {
/* Plane is stored uncompressed */
for (i = 0; i < height; i++) {
memcpy(dst + (i * stride), src, width);
src += width;
}
}
} else if (esc_count == 0xff) {
/* Plane is a solid run of 0 bytes */
for (i = 0; i < height; i++)
memset(dst + i * stride, 0, width);
} else {
av_log(l->avctx, AV_LOG_ERROR,
"Invalid zero run escape code! (%#x)\n", esc_count);
return -1;
}
for (i = 0; i < height; i++) {
lag_pred_line(l, dst, width, stride, i);
dst += stride;
}
return 0;
}
/**
* Decode a frame.
* @param avctx codec context
* @param data output AVFrame
* @param data_size size of output data or 0 if no picture is returned
* @param avpkt input packet
* @return number of consumed bytes on success or negative if decode fails
*/
static int lag_decode_frame(AVCodecContext *avctx,
void *data, int *data_size, AVPacket *avpkt)
{
const uint8_t *buf = avpkt->data;
int buf_size = avpkt->size;
LagarithContext *l = avctx->priv_data;
AVFrame *const p = &l->picture;
uint8_t frametype = 0;
uint32_t offset_gu = 0, offset_bv = 0, offset_ry = 9;
AVFrame *picture = data;
if (p->data[0])
avctx->release_buffer(avctx, p);
p->reference = 0;
p->key_frame = 1;
frametype = buf[0];
offset_gu = AV_RL32(buf + 1);
offset_bv = AV_RL32(buf + 5);
switch (frametype) {
case FRAME_ARITH_YV12:
avctx->pix_fmt = PIX_FMT_YUV420P;
if (avctx->get_buffer(avctx, p) < 0) {
av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
return -1;
}
lag_decode_arith_plane(l, p->data[0], avctx->width, avctx->height,
p->linesize[0], buf + offset_ry,
buf_size);
lag_decode_arith_plane(l, p->data[2], avctx->width / 2,
avctx->height / 2, p->linesize[2],
buf + offset_gu, buf_size);
lag_decode_arith_plane(l, p->data[1], avctx->width / 2,
avctx->height / 2, p->linesize[1],
buf + offset_bv, buf_size);
break;
default:
av_log(avctx, AV_LOG_ERROR,
"Unsupported Lagarith frame type: %#x\n", frametype);
return -1;
}
*picture = *p;
*data_size = sizeof(AVFrame);
return buf_size;
}
static av_cold int lag_decode_init(AVCodecContext *avctx)
{
LagarithContext *l = avctx->priv_data;
l->avctx = avctx;
dsputil_init(&l->dsp, avctx);
return 0;
}
static av_cold int lag_decode_end(AVCodecContext *avctx)
{
LagarithContext *l = avctx->priv_data;
if (l->picture.data[0])
avctx->release_buffer(avctx, &l->picture);
return 0;
}
AVCodec lagarith_decoder = {
"lagarith",
CODEC_TYPE_VIDEO,
CODEC_ID_LAGARITH,
sizeof(LagarithContext),
lag_decode_init,
NULL,
lag_decode_end,
lag_decode_frame,
CODEC_CAP_DR1,
.long_name = NULL_IF_CONFIG_SMALL("Lagarith lossless"),
};

58
libavcodec/lagarithrac.c Normal file
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@ -0,0 +1,58 @@
/*
* Lagarith range decoder
* Copyright (c) 2009 Nathan Caldwell <saintdev (at) gmail.com>
* Copyright (c) 2009 David Conrad
*
* 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
*/
/**
* @file libavcodec/lagarithrac.c
* Lagarith range decoder
* @author Nathan Caldwell
* @author David Conrad
*/
#include "get_bits.h"
#include "lagarithrac.h"
void lag_rac_init(lag_rac *l, GetBitContext *gb, int length)
{
int i, j;
/* According to reference decoder "1st byte is garbage",
* however, it gets skipped by the call to align_get_bits()
*/
align_get_bits(gb);
l->bytestream_start =
l->bytestream = gb->buffer + get_bits_count(gb) / 8;
l->bytestream_end = l->bytestream_start + length;
l->range = 0x80;
l->low = *l->bytestream >> 1;
l->hash_shift = FFMAX(l->scale - 8, 0);
for (i = j = 0; i < 256; i++) {
unsigned r = i << l->hash_shift;
while (l->prob[j + 1] <= r)
j++;
l->range_hash[i] = j;
}
/* Add conversion factor to hash_shift so we don't have to in lag_get_rac. */
l->hash_shift += 23;
}

116
libavcodec/lagarithrac.h Normal file
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@ -0,0 +1,116 @@
/*
* Lagarith range decoder
* Copyright (c) 2009 Nathan Caldwell <saintdev (at) gmail.com>
* Copyright (c) 2009 David Conrad
*
* 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
*/
/**
* @file libavcodec/lagarithrac.h
* Lagarith range decoder
* @author Nathan Caldwell
* @author David Conrad
*/
#ifndef AVCODEC_LAGARITHRAC_H
#define AVCODEC_LAGARITHRAC_H
#include <stdint.h>
#include "libavutil/common.h"
#include "libavutil/intreadwrite.h"
#include "avcodec.h"
#include "get_bits.h"
typedef struct lag_rac {
AVCodecContext *avctx;
unsigned low;
unsigned range;
unsigned scale; /*!< Number of bits of precision in range. */
unsigned hash_shift; /*!< Number of bits to shift to calculate hash for radix search. */
const uint8_t *bytestream_start; /*!< Start of input bytestream. */
const uint8_t *bytestream; /*!< Current position in input bytestream. */
const uint8_t *bytestream_end; /*!< End position of input bytestream. */
uint32_t prob[258]; /*!< Table of cumulative probability for each symbol. */
uint8_t range_hash[256]; /*!< Hash table mapping upper byte to approximate symbol. */
} lag_rac;
void lag_rac_init(lag_rac *l, GetBitContext *gb, int length);
/* TODO: Optimize */
static inline void lag_rac_refill(lag_rac *l)
{
while (l->range <= 0x800000) {
l->low <<= 8;
l->range <<= 8;
l->low |= 0xff & (AV_RB16(l->bytestream) >> 1);
if (l->bytestream < l->bytestream_end)
l->bytestream++;
}
}
/**
* Decode a single byte from the compressed plane described by *l.
* @param l pointer to lag_rac for the current plane
* @return next byte of decoded data
*/
static inline uint8_t lag_get_rac(lag_rac *l)
{
unsigned range_scaled, low_scaled, div;
int val;
uint8_t shift;
lag_rac_refill(l);
range_scaled = l->range >> l->scale;
if (l->low < range_scaled * l->prob[255]) {
/* val = 0 is frequent enough to deserve a shortcut */
if (l->low < range_scaled * l->prob[1]) {
val = 0;
} else {
/* FIXME __builtin_clz is ~20% faster here, but not allowed in generic code. */
shift = 30 - av_log2(range_scaled);
div = ((range_scaled << shift) + (1 << 23) - 1) >> 23;
/* low>>24 ensures that any cases too big for exact FASTDIV are
* under- rather than over-estimated
*/
low_scaled = FASTDIV(l->low - (l->low >> 24), div);
shift -= l->hash_shift;
shift &= 31;
low_scaled = (low_scaled << shift) | (low_scaled >> (32 - shift));
/* low_scaled is now a lower bound of low/range_scaled */
val = l->range_hash[(uint8_t) low_scaled];
while (l->low >= range_scaled * l->prob[val + 1])
val++;
}
l->range = range_scaled * (l->prob[val + 1] - l->prob[val]);
} else {
val = 255;
l->range -= range_scaled * l->prob[255];
}
l->low -= range_scaled * l->prob[val];
return val;
}
#endif /* AVCODEC_LAGARITHRAC_H */

1
libavformat/riff.c
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@ -257,6 +257,7 @@ const AVCodecTag ff_codec_bmp_tags[] = {
{ CODEC_ID_AURA2, MKTAG('A', 'U', 'R', '2') },
{ CODEC_ID_DPX, MKTAG('d', 'p', 'x', ' ') },
{ CODEC_ID_KGV1, MKTAG('K', 'G', 'V', '1') },
{ CODEC_ID_LAGARITH, MKTAG('L', 'A', 'G', 'S') },
{ CODEC_ID_NONE, 0 }
};