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FFmpeg/libavcodec/dpx.c
Georg Lippitsch 05b7315412 Fix DPX decoder 
Rewrite the DPX decoder to work with provided sample DPXs at
http://samples.ffmpeg.org/image-samples/dpx_samples.zip

The decoder could only decode 8 and 10 bit without alpha correctly,
failing or even crashing at other flavors. This patch aims to fix
these issues, properly decoding all variants of DPX provided in the
referenced DPX sample zip. For 10 and 12 bit, the alpha channel
is ignored, but decoding is still possible.

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
2012-10-13 00:31:21 +02:00

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/*
* DPX (.dpx) 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
*/
#include "libavutil/intreadwrite.h"
#include "libavutil/imgutils.h"
#include "bytestream.h"
#include "avcodec.h"
typedef struct DPXContext {
AVFrame picture;
} DPXContext;
static unsigned int read32(const uint8_t **ptr, int is_big)
{
unsigned int temp;
if (is_big) {
temp = AV_RB32(*ptr);
} else {
temp = AV_RL32(*ptr);
}
*ptr += 4;
return temp;
}
static uint16_t read10in32(const uint8_t **ptr, uint32_t * lbuf,
int * n_datum, int is_big)
{
if (*n_datum)
(*n_datum)--;
else {
*lbuf = read32(ptr, is_big);
*n_datum = 2;
}
*lbuf = (*lbuf << 10) | (*lbuf >> 22);
return *lbuf & 0x3FF;
}
static int decode_frame(AVCodecContext *avctx,
void *data,
int *data_size,
AVPacket *avpkt)
{
const uint8_t *buf = avpkt->data;
int buf_size = avpkt->size;
DPXContext *const s = avctx->priv_data;
AVFrame *picture = data;
AVFrame *const p = &s->picture;
uint8_t *ptr[AV_NUM_DATA_POINTERS];
unsigned int offset;
int magic_num, endian;
int x, y, i;
int w, h, bits_per_color, descriptor, elements, packing, total_size;
unsigned int rgbBuffer = 0;
int n_datum = 0;
if (avpkt->size <= 1634) {
av_log(avctx, AV_LOG_ERROR, "Packet too small for DPX header\n");
return AVERROR_INVALIDDATA;
}
magic_num = AV_RB32(buf);
buf += 4;
/* Check if the files "magic number" is "SDPX" which means it uses
* big-endian or XPDS which is for little-endian files */
if (magic_num == AV_RL32("SDPX")) {
endian = 0;
} else if (magic_num == AV_RB32("SDPX")) {
endian = 1;
} else {
av_log(avctx, AV_LOG_ERROR, "DPX marker not found\n");
return -1;
}
offset = read32(&buf, endian);
if (avpkt->size <= offset) {
av_log(avctx, AV_LOG_ERROR, "Invalid data start offset\n");
return AVERROR_INVALIDDATA;
}
// Need to end in 0x304 offset from start of file
buf = avpkt->data + 0x304;
w = read32(&buf, endian);
h = read32(&buf, endian);
// Need to end in 0x320 to read the descriptor
buf += 20;
descriptor = buf[0];
// Need to end in 0x323 to read the bits per color
buf += 3;
avctx->bits_per_raw_sample =
bits_per_color = buf[0];
buf++;
packing = *((uint16_t*)buf);
buf += 824;
avctx->sample_aspect_ratio.num = read32(&buf, endian);
avctx->sample_aspect_ratio.den = read32(&buf, endian);
if (avctx->sample_aspect_ratio.num > 0 && avctx->sample_aspect_ratio.den > 0)
av_reduce(&avctx->sample_aspect_ratio.num, &avctx->sample_aspect_ratio.den,
avctx->sample_aspect_ratio.num, avctx->sample_aspect_ratio.den,
0x10000);
else
avctx->sample_aspect_ratio = (AVRational){ 0, 1 };
switch (descriptor) {
case 51: // RGBA
elements = 4;
break;
case 50: // RGB
elements = 3;
break;
default:
av_log(avctx, AV_LOG_ERROR, "Unsupported descriptor %d\n", descriptor);
return -1;
}
switch (bits_per_color) {
case 8:
if (elements == 4) {
avctx->pix_fmt = AV_PIX_FMT_RGBA;
} else {
avctx->pix_fmt = AV_PIX_FMT_RGB24;
}
total_size = avctx->width * avctx->height * elements;
break;
case 10:
if (!packing) {
av_log(avctx, AV_LOG_ERROR, "Packing to 32bit required\n");
return -1;
}
avctx->pix_fmt = AV_PIX_FMT_GBRP10;
total_size = (4 * avctx->width * avctx->height * elements) / 3;
break;
case 12:
if (!packing) {
av_log(avctx, AV_LOG_ERROR, "Packing to 16bit required\n");
return -1;
}
if (endian) {
avctx->pix_fmt = AV_PIX_FMT_GBRP12BE;
} else {
avctx->pix_fmt = AV_PIX_FMT_GBRP12LE;
}
total_size = 2 * avctx->width * avctx->height * elements;
break;
case 16:
if (endian) {
avctx->pix_fmt = elements == 4 ? AV_PIX_FMT_RGBA64BE : AV_PIX_FMT_RGB48BE;
} else {
avctx->pix_fmt = elements == 4 ? AV_PIX_FMT_RGBA64LE : AV_PIX_FMT_RGB48LE;
}
total_size = 2 * avctx->width * avctx->height * elements;
break;
default:
av_log(avctx, AV_LOG_ERROR, "Unsupported color depth : %d\n", bits_per_color);
return -1;
}
if (s->picture.data[0])
avctx->release_buffer(avctx, &s->picture);
if (av_image_check_size(w, h, 0, avctx))
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;
}
// Move pointer to offset from start of file
buf = avpkt->data + offset;
for (i=0; i<AV_NUM_DATA_POINTERS; i++)
ptr[i] = p->data[i];
if (total_size > avpkt->size) {
av_log(avctx, AV_LOG_ERROR, "Overread buffer. Invalid header?\n");
return -1;
}
switch (bits_per_color) {
case 10:
for (x = 0; x < avctx->height; x++) {
uint16_t *dst[3] = {(uint16_t*)ptr[0],
(uint16_t*)ptr[1],
(uint16_t*)ptr[2]};
for (y = 0; y < avctx->width; y++) {
*dst[2]++ = read10in32(&buf, &rgbBuffer,
&n_datum, endian);
*dst[0]++ = read10in32(&buf, &rgbBuffer,
&n_datum, endian);
*dst[1]++ = read10in32(&buf, &rgbBuffer,
&n_datum, endian);
// For 10 bit, ignore alpha
if (elements == 4)
read10in32(&buf, &rgbBuffer,
&n_datum, endian);
}
for (i = 0; i < 3; i++)
ptr[i] += p->linesize[i];
}
break;
case 12:
for (x = 0; x < avctx->height; x++) {
uint16_t *dst[3] = {(uint16_t*)ptr[0],
(uint16_t*)ptr[1],
(uint16_t*)ptr[2]};
for (y = 0; y < avctx->width; y++) {
*dst[2] = *((uint16_t*)buf);
*dst[2] = (*dst[2] >> 4) | (*dst[2] << 12);
dst[2]++;
buf += 2;
*dst[0] = *((uint16_t*)buf);
*dst[0] = (*dst[0] >> 4) | (*dst[0] << 12);
dst[0]++;
buf += 2;
*dst[1] = *((uint16_t*)buf);
*dst[1] = (*dst[1] >> 4) | (*dst[1] << 12);
dst[1]++;
buf += 2;
// For 12 bit, ignore alpha
if (elements == 4)
buf += 2;
}
for (i = 0; i < 3; i++)
ptr[i] += p->linesize[i];
}
break;
case 16:
elements *= 2;
case 8:
for (x = 0; x < avctx->height; x++) {
memcpy(ptr[0], buf, elements*avctx->width);
ptr[0] += p->linesize[0];
buf += elements*avctx->width;
}
break;
}
*picture = s->picture;
*data_size = sizeof(AVPicture);
return buf_size;
}
static av_cold int decode_init(AVCodecContext *avctx)
{
DPXContext *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)
{
DPXContext *s = avctx->priv_data;
if (s->picture.data[0])
avctx->release_buffer(avctx, &s->picture);
return 0;
}
AVCodec ff_dpx_decoder = {
.name = "dpx",
.type = AVMEDIA_TYPE_VIDEO,
.id = AV_CODEC_ID_DPX,
.priv_data_size = sizeof(DPXContext),
.init = decode_init,
.close = decode_end,
.decode = decode_frame,
.capabilities = CODEC_CAP_DR1,
.long_name = NULL_IF_CONFIG_SMALL("DPX image"),
};
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