Commit ba83c4bf authored by Nicolas George's avatar Nicolas George
Browse files

MJPEG/AVI1 to JPEG/JFIF bitstream filter.

Originally committed as revision 25721 to svn://
parent 2c5168af
......@@ -53,6 +53,7 @@ version <next>:
- single stream LATM/LOAS decoder
- setpts filter added
- Win64 support for optimized asm functions
- MJPEG/AVI1 to JPEG/JFIF bitstream filter
version 0.6:
......@@ -25,6 +25,43 @@ Below is a description of the currently available bitstream filters.
@section imx_dump_header
@section mjpeg2jpeg
Convert MJPEG/AVI1 packets to full JPEG/JFIF packets.
MJPEG is a video codec wherein each video frame is essentially a
JPEG image. The individual frames can be extracted without loss,
e.g. by
ffmpeg -i ../some_mjpeg.avi -vcodec copy frames_%d.jpg
@end example
Unfortunately, these chunks are incomplete JPEG images, because
they lack the DHT segment required for decoding. Quoting from
Avery Lee, writing in the newsgroup in 2001,
commented that "MJPEG, or at least the MJPEG in AVIs having the
MJPG fourcc, is restricted JPEG with a fixed -- and *omitted* --
Huffman table. The JPEG must be YCbCr colorspace, it must be 4:2:2,
and it must use basic Huffman encoding, not arithmetic or
progressive. . . . You can indeed extract the MJPEG frames and
decode them with a regular JPEG decoder, but you have to prepend
the DHT segment to them, or else the decoder won't have any idea
how to decompress the data. The exact table necessary is given in
the OpenDML spec."
This bitstream filter patches the header of frames extracted from an MJPEG
stream (carrying the AVI1 header ID and lacking a DHT segment) to
produce fully qualified JPEG images.
ffmpeg -i mjpeg-movie.avi -vcodec copy -vbsf mjpeg2jpeg frame_%d.jpg
exiftran -i -9 frame*.jpg
ffmpeg -i frame_%d.jpg -vcodec copy rotated.avi
@end example
@section mjpega_dump_header
@section movsub
......@@ -522,7 +522,7 @@ Force video tag/fourcc.
@item -qphist
Show QP histogram.
@item -vbsf @var{bitstream_filter}
Bitstream filters available are "dump_extra", "remove_extra", "noise", "h264_mp4toannexb", "imxdump", "mjpegadump".
Bitstream filters available are "dump_extra", "remove_extra", "noise", "h264_mp4toannexb", "imxdump", "mjpegadump", "mjpeg2jpeg".
ffmpeg -i h264.mp4 -vcodec copy -vbsf h264_mp4toannexb -an out.h264
@end example
......@@ -602,6 +602,7 @@ OBJS-$(CONFIG_CHOMP_BSF) += chomp_bsf.o
OBJS-$(CONFIG_DUMP_EXTRADATA_BSF) += dump_extradata_bsf.o
OBJS-$(CONFIG_H264_MP4TOANNEXB_BSF) += h264_mp4toannexb_bsf.o
OBJS-$(CONFIG_IMX_DUMP_HEADER_BSF) += imx_dump_header_bsf.o
OBJS-$(CONFIG_MJPEG2JPEG_BSF) += mjpeg2jpeg_bsf.o
OBJS-$(CONFIG_MJPEGA_DUMP_HEADER_BSF) += mjpega_dump_header_bsf.o
OBJS-$(CONFIG_MOV2TEXTSUB_BSF) += movsub_bsf.o
OBJS-$(CONFIG_MP3_HEADER_COMPRESS_BSF) += mp3_header_compress_bsf.o
......@@ -394,6 +394,7 @@ void avcodec_register_all(void)
REGISTER_BSF (H264_MP4TOANNEXB, h264_mp4toannexb);
REGISTER_BSF (IMX_DUMP_HEADER, imx_dump_header);
REGISTER_BSF (MJPEGA_DUMP_HEADER, mjpega_dump_header);
REGISTER_BSF (MP3_HEADER_COMPRESS, mp3_header_compress);
REGISTER_BSF (MP3_HEADER_DECOMPRESS, mp3_header_decompress);
* 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
* 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 "avcodec.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(AVBitStreamFilterContext *bsfc,
AVCodecContext *avctx, const char *args,
uint8_t **poutbuf, int *poutbuf_size,
const uint8_t *buf, int buf_size,
int keyframe)
int input_skip, output_size;
uint8_t *output, *out;
if (buf_size < 12) {
av_log(avctx, AV_LOG_ERROR, "input is truncated\n");
if (memcmp("AVI1", buf + 6, 4)) {
av_log(avctx, AV_LOG_ERROR, "input is not MJPEG/AVI1\n");
input_skip = (buf[4] << 8) + buf[5] + 4;
if (buf_size < input_skip) {
av_log(avctx, AV_LOG_ERROR, "input is truncated\n");
output_size = buf_size - input_skip +
sizeof(jpeg_header) + dht_segment_size;
output = out = av_malloc(output_size);
if (!output)
out = append(out, jpeg_header, sizeof(jpeg_header));
out = append_dht_segment(out);
out = append(out, buf + input_skip, buf_size - input_skip);
*poutbuf = output;
*poutbuf_size = output_size;
return 1;
AVBitStreamFilter mjpeg2jpeg_bsf = {
.name = "mjpeg2jpeg",
.priv_data_size = 0,
.filter = mjpeg2jpeg_filter,
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