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FFmpeg/libavcodec/lagarith.c
Andreas Rheinhardt 4243da4ff4 avcodec/codec_internal: Use union for FFCodec decode/encode callbacks 
This is possible, because every given FFCodec has to implement
exactly one of these. Doing so decreases sizeof(FFCodec) and
therefore decreases the size of the binary.
Notice that in case of position-independent code the decrease
is in .data.rel.ro, so that this translates to decreased
memory consumption.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
2022-04-05 20:02:37 +02:00

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/*
* 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
* Lagarith lossless decoder
* @author Nathan Caldwell
*/
#include <inttypes.h>
#include "avcodec.h"
#include "codec_internal.h"
#include "get_bits.h"
#include "mathops.h"
#include "lagarithrac.h"
#include "lossless_videodsp.h"
#include "thread.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;
LLVidDSPContext llviddsp;
int zeros; /**< number of consecutive zero bytes encountered */
int zeros_rem; /**< number of zero bytes remaining to output */
} LagarithContext;
/**
* Compute the 52-bit 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 52-bit 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 32-bit integer factor
* @param mantissa mantissa of f with exponent 0
* @return 32-bit 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 += 1LL << av_log2(h >> 21);
h += l >> 32;
return h >> 20;
}
static uint8_t lag_calc_zero_run(int8_t x)
{
return (x * 2) ^ (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 AVERROR_INVALIDDATA;
} else if (bits == 0) {
*value = 0;
return 0;
}
val = get_bits_long(gb, bits);
val |= 1U << 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;
int nnz = 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 AVERROR_INVALIDDATA;
}
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 AVERROR_INVALIDDATA;
}
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 AVERROR_INVALIDDATA;
}
if (prob > 256 - i)
prob = 256 - i;
for (j = 0; j < prob; j++)
rac->prob[++i] = 0;
}else {
nnz++;
}
}
if (!cumul_prob) {
av_log(rac->avctx, AV_LOG_ERROR, "All probabilities are 0!\n");
return AVERROR_INVALIDDATA;
}
if (nnz == 1 && (show_bits_long(gb, 32) & 0xFFFFFF)) {
return AVERROR_INVALIDDATA;
}
/* 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 <= 128; i++) {
rac->prob[i] = softfloat_mul(rac->prob[i], mul);
scaled_cumul_prob += rac->prob[i];
}
if (scaled_cumul_prob <= 0) {
av_log(rac->avctx, AV_LOG_ERROR, "Scaled probabilities invalid\n");
return AVERROR_INVALIDDATA;
}
for (; i < 257; i++) {
rac->prob[i] = softfloat_mul(rac->prob[i], mul);
scaled_cumul_prob += rac->prob[i];
}
scale_factor++;
if (scale_factor >= 32U)
return AVERROR_INVALIDDATA;
cumulative_target = 1U << scale_factor;
if (scaled_cumul_prob > cumulative_target) {
av_log(rac->avctx, AV_LOG_ERROR,
"Scaled probabilities are larger than target!\n");
return AVERROR_INVALIDDATA;
}
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 negligible and fixing it
* // breaks backwards compatibility
* b =- (signed int)b;
* b &= 0xFF;
* } else {
* b++;
* b &= 0x7f;
* }
*/
}
}
if (scale_factor > 23)
return AVERROR_INVALIDDATA;
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_pred in huffyuvdsp.h.
* However the &0xFF on the gradient predictor yields 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->llviddsp.add_left_pred(buf, buf, width, 0);
} else {
/* Left pixel is actually prev_row[width] */
L = buf[width - stride - 1];
if (line == 1) {
/* Second line, left predict first pixel, the rest of the line is median predicted
* NOTE: In the case of RGB this pixel is top predicted */
TL = l->avctx->pix_fmt == AV_PIX_FMT_YUV420P ? buf[-stride] : L;
} else {
/* Top left is 2 rows back, last pixel */
TL = buf[width - (2 * stride) - 1];
}
add_lag_median_prediction(buf, buf - stride, buf,
width, &L, &TL);
}
}
static void lag_pred_line_yuy2(LagarithContext *l, uint8_t *buf,
int width, int stride, int line,
int is_luma)
{
int L, TL;
if (!line) {
L= buf[0];
if (is_luma)
buf[0] = 0;
l->llviddsp.add_left_pred(buf, buf, width, 0);
if (is_luma)
buf[0] = L;
return;
}
if (line == 1) {
const int HEAD = is_luma ? 4 : 2;
int i;
L = buf[width - stride - 1];
TL = buf[HEAD - stride - 1];
for (i = 0; i < HEAD; i++) {
L += buf[i];
buf[i] = L;
}
for (; i < width; i++) {
L = mid_pred(L & 0xFF, buf[i - stride], (L + buf[i - stride] - TL) & 0xFF) + buf[i];
TL = buf[i - stride];
buf[i] = L;
}
} else {
TL = buf[width - (2 * stride) - 1];
L = buf[width - stride - 1];
l->llviddsp.add_median_pred(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, const uint8_t *src_end,
int width, int esc_count)
{
int i = 0;
int count;
uint8_t zero_run = 0;
const uint8_t *src_start = src;
uint8_t mask1 = -(esc_count < 2);
uint8_t mask2 = -(esc_count < 3);
uint8_t *end = dst + (width - 2);
avpriv_request_sample(l->avctx, "zero_run_line");
memset(dst, 0, width);
output_zeros:
if (l->zeros_rem) {
count = FFMIN(l->zeros_rem, width - i);
if (end - dst < count) {
av_log(l->avctx, AV_LOG_ERROR, "Too many zeros remaining.\n");
return AVERROR_INVALIDDATA;
}
memset(dst, 0, count);
l->zeros_rem -= count;
dst += count;
}
while (dst < end) {
i = 0;
while (!zero_run && dst + i < end) {
i++;
if (i+2 >= src_end - src)
return AVERROR_INVALIDDATA;
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;
dst += i;
}
}
return src - src_start;
}
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;
GetBitContext gb;
lag_rac rac;
const uint8_t *src_end = src + src_size;
int ret;
rac.avctx = l->avctx;
l->zeros = 0;
if(src_size < 2)
return AVERROR_INVALIDDATA;
esc_count = src[0];
if (esc_count < 4) {
length = width * height;
if(src_size < 5)
return AVERROR_INVALIDDATA;
if (esc_count && AV_RL32(src + 1) < length) {
length = AV_RL32(src + 1);
offset += 4;
}
if ((ret = init_get_bits8(&gb, src + offset, src_size - offset)) < 0)
return ret;
if ((ret = lag_read_prob_header(&rac, &gb)) < 0)
return ret;
ff_lag_rac_init(&rac, &gb, length - stride);
for (i = 0; i < height; i++) {
if (rac.overread > MAX_OVERREAD)
return AVERROR_INVALIDDATA;
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 %"PRIu32")\n", read,
length);
} else if (esc_count < 8) {
esc_count -= 4;
src ++;
src_size --;
if (esc_count > 0) {
/* Zero run coding only, no range coding. */
for (i = 0; i < height; i++) {
int res = lag_decode_zero_run_line(l, dst + (i * stride), src,
src_end, width, esc_count);
if (res < 0)
return res;
src += res;
}
} else {
if (src_size < width * height)
return AVERROR_INVALIDDATA; // buffer not big enough
/* 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 given value */
for (i = 0; i < height; i++)
memset(dst + i * stride, src[1], width);
/* Do not apply prediction.
Note: memset to 0 above, setting first value to src[1]
and applying prediction gives the same result. */
return 0;
} else {
av_log(l->avctx, AV_LOG_ERROR,
"Invalid zero run escape code! (%#x)\n", esc_count);
return AVERROR_INVALIDDATA;
}
if (l->avctx->pix_fmt != AV_PIX_FMT_YUV422P) {
for (i = 0; i < height; i++) {
lag_pred_line(l, dst, width, stride, i);
dst += stride;
}
} else {
for (i = 0; i < height; i++) {
lag_pred_line_yuy2(l, dst, width, stride, i,
width == l->avctx->width);
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, AVFrame *p,
int *got_frame, AVPacket *avpkt)
{
const uint8_t *buf = avpkt->data;
unsigned int buf_size = avpkt->size;
LagarithContext *l = avctx->priv_data;
uint8_t frametype;
uint32_t offset_gu = 0, offset_bv = 0, offset_ry = 9;
uint32_t offs[4];
uint8_t *srcs[4];
int i, j, planes = 3;
int ret = 0;
p->key_frame = 1;
p->pict_type = AV_PICTURE_TYPE_I;
frametype = buf[0];
offset_gu = AV_RL32(buf + 1);
offset_bv = AV_RL32(buf + 5);
switch (frametype) {
case FRAME_SOLID_RGBA:
avctx->pix_fmt = AV_PIX_FMT_GBRAP;
case FRAME_SOLID_GRAY:
if (frametype == FRAME_SOLID_GRAY)
if (avctx->bits_per_coded_sample == 24) {
avctx->pix_fmt = AV_PIX_FMT_GBRP;
} else {
avctx->pix_fmt = AV_PIX_FMT_GBRAP;
planes = 4;
}
if ((ret = ff_thread_get_buffer(avctx, p, 0)) < 0)
return ret;
if (frametype == FRAME_SOLID_RGBA) {
for (i = 0; i < avctx->height; i++) {
memset(p->data[0] + i * p->linesize[0], buf[2], avctx->width);
memset(p->data[1] + i * p->linesize[1], buf[1], avctx->width);
memset(p->data[2] + i * p->linesize[2], buf[3], avctx->width);
memset(p->data[3] + i * p->linesize[3], buf[4], avctx->width);
}
} else {
for (i = 0; i < avctx->height; i++) {
for (j = 0; j < planes; j++)
memset(p->data[j] + i * p->linesize[j], buf[1], avctx->width);
}
}
break;
case FRAME_SOLID_COLOR:
if (avctx->bits_per_coded_sample == 24) {
avctx->pix_fmt = AV_PIX_FMT_GBRP;
} else {
avctx->pix_fmt = AV_PIX_FMT_GBRAP;
}
if ((ret = ff_thread_get_buffer(avctx, p,0)) < 0)
return ret;
for (i = 0; i < avctx->height; i++) {
memset(p->data[0] + i * p->linesize[0], buf[2], avctx->width);
memset(p->data[1] + i * p->linesize[1], buf[1], avctx->width);
memset(p->data[2] + i * p->linesize[2], buf[3], avctx->width);
if (avctx->pix_fmt == AV_PIX_FMT_GBRAP)
memset(p->data[3] + i * p->linesize[3], 0xFFu, avctx->width);
}
break;
case FRAME_ARITH_RGBA:
avctx->pix_fmt = AV_PIX_FMT_GBRAP;
planes = 4;
offset_ry += 4;
offs[3] = AV_RL32(buf + 9);
case FRAME_ARITH_RGB24:
case FRAME_U_RGB24:
if (frametype == FRAME_ARITH_RGB24 || frametype == FRAME_U_RGB24)
avctx->pix_fmt = AV_PIX_FMT_GBRP;
if ((ret = ff_thread_get_buffer(avctx, p, 0)) < 0)
return ret;
offs[0] = offset_bv;
offs[1] = offset_gu;
offs[2] = offset_ry;
for (i = 0; i < planes; i++)
srcs[i] = p->data[i] + (avctx->height - 1) * p->linesize[i];
for (i = 0; i < planes; i++)
if (buf_size <= offs[i]) {
av_log(avctx, AV_LOG_ERROR,
"Invalid frame offsets\n");
return AVERROR_INVALIDDATA;
}
for (i = 0; i < planes; i++) {
ret = lag_decode_arith_plane(l, srcs[i],
avctx->width, avctx->height,
-p->linesize[i], buf + offs[i],
buf_size - offs[i]);
if (ret < 0)
return ret;
}
for (i = 0; i < avctx->height; i++) {
l->llviddsp.add_bytes(p->data[0] + i * p->linesize[0], p->data[1] + i * p->linesize[1], avctx->width);
l->llviddsp.add_bytes(p->data[2] + i * p->linesize[2], p->data[1] + i * p->linesize[1], avctx->width);
}
FFSWAP(uint8_t*, p->data[0], p->data[1]);
FFSWAP(int, p->linesize[0], p->linesize[1]);
FFSWAP(uint8_t*, p->data[2], p->data[1]);
FFSWAP(int, p->linesize[2], p->linesize[1]);
break;
case FRAME_ARITH_YUY2:
avctx->pix_fmt = AV_PIX_FMT_YUV422P;
if ((ret = ff_thread_get_buffer(avctx, p, 0)) < 0)
return ret;
if (offset_ry >= buf_size ||
offset_gu >= buf_size ||
offset_bv >= buf_size) {
av_log(avctx, AV_LOG_ERROR,
"Invalid frame offsets\n");
return AVERROR_INVALIDDATA;
}
ret = lag_decode_arith_plane(l, p->data[0], avctx->width, avctx->height,
p->linesize[0], buf + offset_ry,
buf_size - offset_ry);
if (ret < 0)
return ret;
ret = lag_decode_arith_plane(l, p->data[1], (avctx->width + 1) / 2,
avctx->height, p->linesize[1],
buf + offset_gu, buf_size - offset_gu);
if (ret < 0)
return ret;
ret = lag_decode_arith_plane(l, p->data[2], (avctx->width + 1) / 2,
avctx->height, p->linesize[2],
buf + offset_bv, buf_size - offset_bv);
break;
case FRAME_ARITH_YV12:
avctx->pix_fmt = AV_PIX_FMT_YUV420P;
if ((ret = ff_thread_get_buffer(avctx, p, 0)) < 0)
return ret;
if (offset_ry >= buf_size ||
offset_gu >= buf_size ||
offset_bv >= buf_size) {
av_log(avctx, AV_LOG_ERROR,
"Invalid frame offsets\n");
return AVERROR_INVALIDDATA;
}
ret = lag_decode_arith_plane(l, p->data[0], avctx->width, avctx->height,
p->linesize[0], buf + offset_ry,
buf_size - offset_ry);
if (ret < 0)
return ret;
ret = lag_decode_arith_plane(l, p->data[2], (avctx->width + 1) / 2,
(avctx->height + 1) / 2, p->linesize[2],
buf + offset_gu, buf_size - offset_gu);
if (ret < 0)
return ret;
ret = lag_decode_arith_plane(l, p->data[1], (avctx->width + 1) / 2,
(avctx->height + 1) / 2, p->linesize[1],
buf + offset_bv, buf_size - offset_bv);
break;
default:
av_log(avctx, AV_LOG_ERROR,
"Unsupported Lagarith frame type: %#"PRIx8"\n", frametype);
return AVERROR_PATCHWELCOME;
}
if (ret < 0)
return ret;
*got_frame = 1;
return buf_size;
}
static av_cold int lag_decode_init(AVCodecContext *avctx)
{
LagarithContext *l = avctx->priv_data;
l->avctx = avctx;
ff_llviddsp_init(&l->llviddsp);
return 0;
}
const FFCodec ff_lagarith_decoder = {
.p.name = "lagarith",
.p.long_name = NULL_IF_CONFIG_SMALL("Lagarith lossless"),
.p.type = AVMEDIA_TYPE_VIDEO,
.p.id = AV_CODEC_ID_LAGARITH,
.priv_data_size = sizeof(LagarithContext),
.init = lag_decode_init,
FF_CODEC_DECODE_CB(lag_decode_frame),
.p.capabilities = AV_CODEC_CAP_DR1 | AV_CODEC_CAP_FRAME_THREADS,
.caps_internal = FF_CODEC_CAP_INIT_THREADSAFE,
};
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