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FFmpeg/libavcodec/mjpeg2jpeg_bsf.c
Andreas Rheinhardt 1d333c1547 avcodec/jpegtables: Unavpriv MJPEG-tables
There are seven MJPEG-tables, five small (1x12, 4x17) and two
not small (2x162). These are all avpriv, despite this not being
worthwhile due to the overhead of exporting a symbol: The total
overhead for each symbol consists of two entries in .dynsym (24B each),
one entry in the importing library's .rela.dyn (24B) and one in .got
(8B) as well as 2x2B for symbol versions and 4B for symbol hashes
in the exporting library; in addition to that, the name of the symbol
is included in both exporting and importing libraries, using 2x210 bytes
in this case.
(The above numbers are for a x64 Elf/Linux/GNU system. Other platforms
will give different numbers.)

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
2022-01-04 13:16:50 +01:00

143 lines
4.4 KiB
C

/*
* MJPEG/AVI1 to JPEG/JFIF bitstream format filter
* Copyright (c) 2010 Adrian Daerr and Nicolas George
*
* 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
*/
/*
* Adapted from mjpeg2jpeg.c, with original copyright:
* Paris 2010 Adrian Daerr, public domain
*/
#include <string.h>
#include "libavutil/error.h"
#include "libavutil/intreadwrite.h"
#include "bsf.h"
#include "bsf_internal.h"
#include "jpegtables.h"
#include "mjpeg.h"
static const uint8_t jpeg_header[] = {
0xff, 0xd8, // SOI
0xff, 0xe0, // APP0
0x00, 0x10, // APP0 header size (including
// this field, but excluding preceding)
0x4a, 0x46, 0x49, 0x46, 0x00, // ID string 'JFIF\0'
0x01, 0x01, // version
0x00, // bits per type
0x00, 0x00, // X density
0x00, 0x00, // Y density
0x00, // X thumbnail size
0x00, // Y thumbnail size
};
static const int dht_segment_size = 420;
static const uint8_t dht_segment_head[] = { 0xFF, 0xC4, 0x01, 0xA2, 0x00 };
static const uint8_t dht_segment_frag[] = {
0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09,
0x0a, 0x0b, 0x01, 0x00, 0x03, 0x01, 0x01, 0x01, 0x01, 0x01,
0x01, 0x01, 0x01, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00,
};
static uint8_t *append(uint8_t *buf, const uint8_t *src, int size)
{
memcpy(buf, src, size);
return buf + size;
}
static uint8_t *append_dht_segment(uint8_t *buf)
{
buf = append(buf, dht_segment_head, sizeof(dht_segment_head));
buf = append(buf, ff_mjpeg_bits_dc_luminance + 1, 16);
buf = append(buf, dht_segment_frag, sizeof(dht_segment_frag));
buf = append(buf, ff_mjpeg_val_dc, 12);
*(buf++) = 0x10;
buf = append(buf, ff_mjpeg_bits_ac_luminance + 1, 16);
buf = append(buf, ff_mjpeg_val_ac_luminance, 162);
*(buf++) = 0x11;
buf = append(buf, ff_mjpeg_bits_ac_chrominance + 1, 16);
buf = append(buf, ff_mjpeg_val_ac_chrominance, 162);
return buf;
}
static int mjpeg2jpeg_filter(AVBSFContext *ctx, AVPacket *out)
{
AVPacket *in;
int ret = 0;
int input_skip, output_size;
uint8_t *output;
ret = ff_bsf_get_packet(ctx, &in);
if (ret < 0)
return ret;
if (in->size < 12) {
av_log(ctx, AV_LOG_ERROR, "input is truncated\n");
ret = AVERROR_INVALIDDATA;
goto fail;
}
if (AV_RB16(in->data) != 0xffd8) {
av_log(ctx, AV_LOG_ERROR, "input is not MJPEG\n");
ret = AVERROR_INVALIDDATA;
goto fail;
}
if (in->data[2] == 0xff && in->data[3] == APP0) {
input_skip = (in->data[4] << 8) + in->data[5] + 4;
} else {
input_skip = 2;
}
if (in->size < input_skip) {
av_log(ctx, AV_LOG_ERROR, "input is truncated\n");
ret = AVERROR_INVALIDDATA;
goto fail;
}
output_size = in->size - input_skip +
sizeof(jpeg_header) + dht_segment_size;
ret = av_new_packet(out, output_size);
if (ret < 0)
goto fail;
output = out->data;
output = append(output, jpeg_header, sizeof(jpeg_header));
output = append_dht_segment(output);
output = append(output, in->data + input_skip, in->size - input_skip);
ret = av_packet_copy_props(out, in);
if (ret < 0)
goto fail;
fail:
if (ret < 0)
av_packet_unref(out);
av_packet_free(&in);
return ret;
}
static const enum AVCodecID codec_ids[] = {
AV_CODEC_ID_MJPEG, AV_CODEC_ID_NONE,
};
const AVBitStreamFilter ff_mjpeg2jpeg_bsf = {
.name = "mjpeg2jpeg",
.filter = mjpeg2jpeg_filter,
.codec_ids = codec_ids,
};