MJPEG/AVI1 to JPEG/JFIF bitstream filter.

Originally committed as revision 25721 to svn://svn.ffmpeg.org/ffmpeg/trunk

Changelog

@@ -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:

doc/bitstream_filters.texi

@@ -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
+
+@example
+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
+@url{http://www.digitalpreservation.gov/formats/fdd/fdd000063.shtml}:
+
+Avery Lee, writing in the rec.video.desktop 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.
+
+@example
+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

doc/ffmpeg-doc.texi

@@ -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".
 @example
 ffmpeg -i h264.mp4 -vcodec copy -vbsf h264_mp4toannexb -an out.h264
 @end example

libavcodec/Makefile

@@ -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

libavcodec/allcodecs.c

@@ -394,6 +394,7 @@ void avcodec_register_all(void)
     REGISTER_BSF     (DUMP_EXTRADATA, dump_extradata);
     REGISTER_BSF     (H264_MP4TOANNEXB, h264_mp4toannexb);
     REGISTER_BSF     (IMX_DUMP_HEADER, imx_dump_header);
+    REGISTER_BSF     (MJPEG2JPEG, mjpeg2jpeg);
     REGISTER_BSF     (MJPEGA_DUMP_HEADER, mjpega_dump_header);
     REGISTER_BSF     (MP3_HEADER_COMPRESS, mp3_header_compress);
     REGISTER_BSF     (MP3_HEADER_DECOMPRESS, mp3_header_decompress);

libavcodec/mjpeg2jpeg_bsf.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 "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");
+        return AVERROR_INVALIDDATA;
+    }
+    if (memcmp("AVI1", buf + 6, 4)) {
+        av_log(avctx, AV_LOG_ERROR, "input is not MJPEG/AVI1\n");
+        return AVERROR_INVALIDDATA;
+    }
+    input_skip = (buf[4] << 8) + buf[5] + 4;
+    if (buf_size < input_skip) {
+        av_log(avctx, AV_LOG_ERROR, "input is truncated\n");
+        return AVERROR_INVALIDDATA;
+    }
+    output_size = buf_size - input_skip +
+                  sizeof(jpeg_header) + dht_segment_size;
+    output = out = av_malloc(output_size);
+    if (!output)
+        return AVERROR(ENOMEM);
+    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,
+};