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ffmpeg/libavcodec/exr.c

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/*
* OpenEXR (.exr) image decoder
* Copyright (c) 2009 Jimmy Christensen
*
* 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
* OpenEXR decoder
* @author Jimmy Christensen
*
* For more information on the OpenEXR format, visit:
* http://openexr.com/
*
* exr_flt2uint() and exr_halflt2uint() is credited to Reimar Döffinger
*/
#include "avcodec.h"
#include "bytestream.h"
#include "libavutil/imgutils.h"
enum ExrCompr {
EXR_RAW = 0,
EXR_RLE = 1,
EXR_ZIP1 = 2,
EXR_ZIP16 = 3,
EXR_PIZ = 4,
EXR_B44 = 6
};
typedef struct EXRContext {
AVFrame picture;
int compr;
int bits_per_color_id;
int8_t channel_offsets[4]; // 0 = red, 1 = green, 2 = blue and 3 = alpha
} EXRContext;
/**
* Converts from 32-bit float as uint32_t to uint16_t
*
* @param v 32-bit float
* @return normalized 16-bit unsigned int
*/
static inline uint16_t exr_flt2uint(uint32_t v)
{
unsigned int exp = v >> 23;
// "HACK": negative values result in exp< 0, so clipping them to 0
// is also handled by this condition, avoids explicit check for sign bit.
if (exp<= 127 + 7 - 24) // we would shift out all bits anyway
return 0;
if (exp >= 127)
return 0xffff;
v &= 0x007fffff;
return (v + (1 << 23)) >> (127 + 7 - exp);
}
/**
* Converts from 16-bit float as uint16_t to uint16_t
*
* @param v 16-bit float
* @return normalized 16-bit unsigned int
*/
static inline uint16_t exr_halflt2uint(uint16_t v)
{
unsigned exp = 14 - (v >> 10);
if (exp >= 14) {
if (exp == 14) return (v >> 9) & 1;
else return (v & 0x8000) ? 0 : 0xffff;
}
v <<= 6;
return (v + (1 << 16)) >> (exp + 1);
}
/**
* Gets the size of the header variable
*
* @param **buf the current pointer location in the header where
* the variable data starts
* @param *buf_end pointer location of the end of the buffer
* @return size of variable data
*/
static unsigned int get_header_variable_length(const uint8_t **buf,
const uint8_t *buf_end)
{
unsigned int variable_buffer_data_size = bytestream_get_le32(buf);
if (variable_buffer_data_size >= buf_end - *buf)
return 0;
return variable_buffer_data_size;
}
/**
* Checks if the variable name corresponds with it's data type
*
* @param *avctx the AVCodecContext
* @param **buf the current pointer location in the header where
* the variable name starts
* @param *buf_end pointer location of the end of the buffer
* @param *value_name name of the varible to check
* @param *value_type type of the varible to check
* @param minimum_length minimum length of the variable data
* @param variable_buffer_data_size variable length read from the header
* after it's checked
* @return negative if variable is invalid
*/
static int check_header_variable(AVCodecContext *avctx,
const uint8_t **buf,
const uint8_t *buf_end,
const char *value_name,
const char *value_type,
unsigned int minimum_length,
unsigned int *variable_buffer_data_size)
{
if (buf_end - *buf >= minimum_length && !strcmp(*buf, value_name)) {
*buf += strlen(value_name)+1;
if (!strcmp(*buf, value_type)) {
*buf += strlen(value_type)+1;
*variable_buffer_data_size = get_header_variable_length(buf, buf_end);
if (!*variable_buffer_data_size)
av_log(avctx, AV_LOG_ERROR, "Incomplete header\n");
if (*variable_buffer_data_size > buf_end - *buf)
return -1;
return 1;
}
*buf -= strlen(value_name)+1;
av_log(avctx, AV_LOG_WARNING, "Unknown data type for header variable %s\n", value_name);
}
return -1;
}
static int decode_frame(AVCodecContext *avctx,
void *data,
int *data_size,
AVPacket *avpkt)
{
const uint8_t *buf = avpkt->data;
unsigned int buf_size = avpkt->size;
const uint8_t *buf_end = buf + buf_size;
EXRContext *const s = avctx->priv_data;
AVFrame *picture = data;
AVFrame *const p = &s->picture;
uint8_t *ptr;
int i, x, y, stride, magic_number, version_flag;
int w = 0;
int h = 0;
unsigned int xmin = ~0;
unsigned int xmax = ~0;
unsigned int ymin = ~0;
unsigned int ymax = ~0;
unsigned int xdelta = ~0;
unsigned int current_channel_offset = 0;
s->channel_offsets[0] = -1;
s->channel_offsets[1] = -1;
s->channel_offsets[2] = -1;
s->channel_offsets[3] = -1;
s->bits_per_color_id = -1;
if (buf_end - buf < 10) {
av_log(avctx, AV_LOG_ERROR, "Too short header to parse\n");
return -1;
}
magic_number = bytestream_get_le32(&buf);
if (magic_number != 20000630) { // As per documentation of OpenEXR it's supposed to be int 20000630 little-endian
av_log(avctx, AV_LOG_ERROR, "Wrong magic number %d\n", magic_number);
return -1;
}
version_flag = bytestream_get_le32(&buf);
if ((version_flag & 0x200) == 0x200) {
av_log(avctx, AV_LOG_ERROR, "Tile based images are not supported\n");
return -1;
}
// Parse the header
while (buf < buf_end && buf[0]) {
unsigned int variable_buffer_data_size;
// Process the channel list
if (check_header_variable(avctx, &buf, buf_end, "channels", "chlist", 38, &variable_buffer_data_size) >= 0) {
const uint8_t *channel_list_end;
if (!variable_buffer_data_size)
return -1;
channel_list_end = buf + variable_buffer_data_size;
while (channel_list_end - buf >= 19) {
int current_bits_per_color_id = -1;
int channel_index = -1;
if (!strcmp(buf, "R"))
channel_index = 0;
if (!strcmp(buf, "G"))
channel_index = 1;
if (!strcmp(buf, "B"))
channel_index = 2;
if (!strcmp(buf, "A"))
channel_index = 3;
while (bytestream_get_byte(&buf) && buf < channel_list_end)
continue; /* skip */
if (channel_list_end - * &buf < 4) {
av_log(avctx, AV_LOG_ERROR, "Incomplete header\n");
return -1;
}
current_bits_per_color_id = bytestream_get_le32(&buf);
if (current_bits_per_color_id > 2) {
av_log(avctx, AV_LOG_ERROR, "Unknown color format\n");
return -1;
}
if (channel_index >= 0) {
if (s->bits_per_color_id != -1 && s->bits_per_color_id != current_bits_per_color_id) {
av_log(avctx, AV_LOG_ERROR, "RGB channels not of the same depth\n");
return -1;
}
s->bits_per_color_id = current_bits_per_color_id;
s->channel_offsets[channel_index] = current_channel_offset;
}
current_channel_offset += 1 << current_bits_per_color_id;
buf += 12;
}
/* Check if all channels are set with an offset or if the channels
* are causing an overflow */
if (FFMIN3(s->channel_offsets[0],
s->channel_offsets[1],
s->channel_offsets[2]) < 0) {
if (s->channel_offsets[0] < 0)
av_log(avctx, AV_LOG_ERROR, "Missing red channel\n");
if (s->channel_offsets[1] < 0)
av_log(avctx, AV_LOG_ERROR, "Missing green channel\n");
if (s->channel_offsets[2] < 0)
av_log(avctx, AV_LOG_ERROR, "Missing blue channel\n");
return -1;
}
buf = channel_list_end;
continue;
}
// Process the dataWindow variable
if (check_header_variable(avctx, &buf, buf_end, "dataWindow", "box2i", 31, &variable_buffer_data_size) >= 0) {
if (!variable_buffer_data_size)
return -1;
xmin = AV_RL32(buf);
ymin = AV_RL32(buf + 4);
xmax = AV_RL32(buf + 8);
ymax = AV_RL32(buf + 12);
xdelta = (xmax-xmin) + 1;
buf += variable_buffer_data_size;
continue;
}
// Process the displayWindow variable
if (check_header_variable(avctx, &buf, buf_end, "displayWindow", "box2i", 34, &variable_buffer_data_size) >= 0) {
if (!variable_buffer_data_size)
return -1;
w = AV_RL32(buf + 8) + 1;
h = AV_RL32(buf + 12) + 1;
buf += variable_buffer_data_size;
continue;
}
// Process the lineOrder variable
if (check_header_variable(avctx, &buf, buf_end, "lineOrder", "lineOrder", 25, &variable_buffer_data_size) >= 0) {
if (!variable_buffer_data_size)
return -1;
if (*buf) {
av_log(avctx, AV_LOG_ERROR, "Doesn't support this line order : %d\n", *buf);
return -1;
}
buf += variable_buffer_data_size;
continue;
}
// Process the compression variable
if (check_header_variable(avctx, &buf, buf_end, "compression", "compression", 29, &variable_buffer_data_size) >= 0) {
if (!variable_buffer_data_size)
return -1;
s->compr = *buf;
switch (s->compr) {
case EXR_RAW:
break;
case EXR_RLE:
case EXR_ZIP1:
case EXR_ZIP16:
case EXR_PIZ:
case EXR_B44:
default:
av_log(avctx, AV_LOG_ERROR, "Compression type %d is not supported\n", s->compr);
return -1;
}
buf += variable_buffer_data_size;
continue;
}
// Check if there is enough bytes for a header
if (buf_end - buf <= 9) {
av_log(avctx, AV_LOG_ERROR, "Incomplete header\n");
return -1;
}
// Process unknown variables
for (i = 0; i < 2; i++) {
// Skip variable name/type
while (++buf < buf_end)
if (buf[0] == 0x0)
break;
}
buf++;
// Skip variable length
if (buf_end - buf >= 5) {
variable_buffer_data_size = get_header_variable_length(&buf, buf_end);
if (!variable_buffer_data_size) {
av_log(avctx, AV_LOG_ERROR, "Incomplete header\n");
return -1;
}
buf += variable_buffer_data_size;
}
}
if (buf >= buf_end) {
av_log(avctx, AV_LOG_ERROR, "Incomplete frame\n");
return -1;
}
buf++;
switch (s->bits_per_color_id) {
case 2: // 32-bit
case 1: // 16-bit
if (s->channel_offsets[3] >= 0)
avctx->pix_fmt = PIX_FMT_RGBA64;
else
avctx->pix_fmt = PIX_FMT_RGB48;
break;
// 8-bit
case 0:
av_log_missing_feature(avctx, "8-bit OpenEXR", 1);
return -1;
default:
av_log(avctx, AV_LOG_ERROR, "Unknown color format : %d\n", s->bits_per_color_id);
return -1;
}
if (s->picture.data[0])
avctx->release_buffer(avctx, &s->picture);
if (av_image_check_size(w, h, 0, avctx))
return -1;
// Verify the xmin, xmax, ymin, ymax and xdelta before setting the actual image size
if (xmin > xmax || ymin > ymax || xdelta != xmax - xmin + 1 || xmax >= w || ymax >= h) {
av_log(avctx, AV_LOG_ERROR, "Wrong sizing or missing size information\n");
return -1;
}
if (w != avctx->width || h != avctx->height) {
avcodec_set_dimensions(avctx, w, h);
}
if (avctx->get_buffer(avctx, p) < 0) {
av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
return -1;
}
ptr = p->data[0];
stride = p->linesize[0];
// Zero out the start if ymin is not 0
for (y = 0; y < ymin; y++) {
memset(ptr, 0, avctx->width * 2 * av_pix_fmt_descriptors[avctx->pix_fmt].nb_components);
ptr += stride;
}
// Process the actual lines
for (y = ymin; y <= ymax; y++) {
uint16_t *ptr_x = (uint16_t *)ptr;
if (buf_end - buf > 8) {
/* Read the lineoffset from the line offset table and add 8 bytes
to skip the coordinates and data size fields */
const uint64_t line_offset = bytestream_get_le64(&buf) + 8;
// Check if the buffer has the required bytes needed from the offset
if (line_offset > avpkt->size - xdelta * current_channel_offset) {
// Line offset is probably wrong and not inside the buffer
av_log(avctx, AV_LOG_WARNING, "Line offset for line %d is out of reach setting it to black\n", y);
memset(ptr_x, 0, avctx->width * 2 * av_pix_fmt_descriptors[avctx->pix_fmt].nb_components);
} else {
const uint8_t *red_channel_buffer = avpkt->data + line_offset + xdelta * s->channel_offsets[0];
const uint8_t *green_channel_buffer = avpkt->data + line_offset + xdelta * s->channel_offsets[1];
const uint8_t *blue_channel_buffer = avpkt->data + line_offset + xdelta * s->channel_offsets[2];
const uint8_t *alpha_channel_buffer = 0;
if (s->channel_offsets[3] >= 0)
alpha_channel_buffer = avpkt->data + line_offset + xdelta * s->channel_offsets[3];
// Zero out the start if xmin is not 0
memset(ptr_x, 0, xmin * 2 * av_pix_fmt_descriptors[avctx->pix_fmt].nb_components);
ptr_x += xmin * av_pix_fmt_descriptors[avctx->pix_fmt].nb_components;
if (s->bits_per_color_id == 2) {
// 32-bit
for (x = 0; x < xdelta; x++) {
*ptr_x++ = exr_flt2uint(bytestream_get_le32(&red_channel_buffer));
*ptr_x++ = exr_flt2uint(bytestream_get_le32(&green_channel_buffer));
*ptr_x++ = exr_flt2uint(bytestream_get_le32(&blue_channel_buffer));
if (alpha_channel_buffer)
*ptr_x++ = exr_flt2uint(bytestream_get_le32(&alpha_channel_buffer));
}
} else {
// 16-bit
for (x = 0; x < xdelta; x++) {
*ptr_x++ = exr_halflt2uint(bytestream_get_le16(&red_channel_buffer));
*ptr_x++ = exr_halflt2uint(bytestream_get_le16(&green_channel_buffer));
*ptr_x++ = exr_halflt2uint(bytestream_get_le16(&blue_channel_buffer));
if (alpha_channel_buffer)
*ptr_x++ = exr_halflt2uint(bytestream_get_le16(&alpha_channel_buffer));
}
}
// Zero out the end if xmax+1 is not w
memset(ptr_x, 0, (avctx->width - (xmax + 1)) * 2 * av_pix_fmt_descriptors[avctx->pix_fmt].nb_components);
ptr_x += (avctx->width - (xmax + 1)) * av_pix_fmt_descriptors[avctx->pix_fmt].nb_components;
}
// Move to next line
ptr += stride;
}
}
// Zero out the end if ymax+1 is not h
for (y = ymax + 1; y < avctx->height; y++) {
memset(ptr, 0, avctx->width * 2 * av_pix_fmt_descriptors[avctx->pix_fmt].nb_components);
ptr += stride;
}
*picture = s->picture;
*data_size = sizeof(AVPicture);
return buf_size;
}
static av_cold int decode_init(AVCodecContext *avctx)
{
EXRContext *s = avctx->priv_data;
avcodec_get_frame_defaults(&s->picture);
avctx->coded_frame = &s->picture;
return 0;
}
static av_cold int decode_end(AVCodecContext *avctx)
{
EXRContext *s = avctx->priv_data;
if (s->picture.data[0])
avctx->release_buffer(avctx, &s->picture);
return 0;
}
AVCodec ff_exr_decoder = {
.name = "exr",
.type = AVMEDIA_TYPE_VIDEO,
.id = CODEC_ID_EXR,
.priv_data_size = sizeof(EXRContext),
.init = decode_init,
.close = decode_end,
.decode = decode_frame,
.long_name = NULL_IF_CONFIG_SMALL("OpenEXR image"),
};
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