Support only streams with Content-Length.
---
It is a quite simple demuxer written while writing a small blogpost about
demuxers. It is apparently useful for at least few people.
libavformat/Makefile | 1 +
libavformat/allformats.c | 2 +-
libavformat/mpjpegdec.c | 210 +++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 212 insertions(+), 1 deletion(-)
create mode 100644 libavformat/mpjpegdec.c
diff --git a/libavformat/Makefile b/libavformat/Makefile
index bdd0e9e..3496c4c 100644
--- a/libavformat/Makefile
+++ b/libavformat/Makefile
@@ -201,6 +201,7 @@ OBJS-$(CONFIG_MPEGPS_DEMUXER) += mpeg.o
OBJS-$(CONFIG_MPEGTS_DEMUXER) += mpegts.o isom.o
OBJS-$(CONFIG_MPEGTS_MUXER) += mpegtsenc.o
OBJS-$(CONFIG_MPEGVIDEO_DEMUXER) += mpegvideodec.o rawdec.o
+OBJS-$(CONFIG_MPJPEG_DEMUXER) += mpjpegdec.o
OBJS-$(CONFIG_MPJPEG_MUXER) += mpjpeg.o
OBJS-$(CONFIG_MSNWC_TCP_DEMUXER) += msnwc_tcp.o
OBJS-$(CONFIG_MTV_DEMUXER) += mtv.o
diff --git a/libavformat/allformats.c b/libavformat/allformats.c
index cb22ae3..1e52143 100644
--- a/libavformat/allformats.c
+++ b/libavformat/allformats.c
@@ -162,7 +162,7 @@ void av_register_all(void)
REGISTER_MUXDEMUX(MPEGTS, mpegts);
REGISTER_DEMUXER (MPEGTSRAW, mpegtsraw);
REGISTER_DEMUXER (MPEGVIDEO, mpegvideo);
- REGISTER_MUXER (MPJPEG, mpjpeg);
+ REGISTER_MUXDEMUX(MPJPEG, mpjpeg);
REGISTER_DEMUXER (MSNWC_TCP, msnwc_tcp);
REGISTER_DEMUXER (MTV, mtv);
REGISTER_DEMUXER (MV, mv);
diff --git a/libavformat/mpjpegdec.c b/libavformat/mpjpegdec.c
new file mode 100644
index 0000000..edcc061
--- /dev/null
+++ b/libavformat/mpjpegdec.c
@@ -0,0 +1,210 @@
+/*
+ * Multipart JPEG format
+ * Copyright (c) 2014 Luca Barbato
+ *
+ * This file is part of Libav.
+ *
+ * Libav 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.
+ *
+ * Libav 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 Libav; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include "libavutil/avstring.h"
+
+#include "avformat.h"
+#include "internal.h"
+
+static int get_line(AVIOContext *pb, char *line, int line_size)
+{
+ int i, ch;
+ char *q = line;
+
+ for (i = 0; !pb->eof_reached; i++) {
+ ch = avio_r8(pb);
+ if (ch == '\n') {
+ if (q > line && q[-1] == '\r')
+ q--;
+ *q = '\0';
+
+ return 0;
+ } else {
+ if ((q - line) < line_size - 1)
+ *q++ = ch;
+ }
+ }
+
+ if (pb->error)
+ return pb->error;
+ return AVERROR_EOF;
+}
+
+static int split_tag_value(char **tag, char **value, char *line)
+{
+ char *p = line;
+
+ while (*p != '\0' && *p != ':')
+ p++;
+ if (*p != ':')
+ return AVERROR_INVALIDDATA;
+
+ *p = '\0';
+ *tag = line;
+
+ p++;
+
+ while (av_isspace(*p))
+ p++;
+
+ *value = p;
+
+ return 0;
+}
+
+static int check_content_type(char *line)
+{
+ char *tag, *value;
+ int ret = split_tag_value(&tag, &value, line);
+
+ if (ret < 0)
+ return ret;
+
+ if (av_strcasecmp(tag, "Content-type") ||
+ av_strcasecmp(value, "image/jpeg"))
+ return AVERROR_INVALIDDATA;
+
+ return 0;
+}
+
+static int mpjpeg_read_probe(AVProbeData *p)
+{
+ AVIOContext *pb;
+ char line[128] = { 0 };
+ int ret;
+
+ pb = avio_alloc_context(p->buf, p->buf_size, 0, NULL, NULL, NULL, NULL);
+ if (!pb)
+ return AVERROR(ENOMEM);
+
+ while (!pb->eof_reached) {
+ ret = get_line(pb, line, sizeof(line));
+ if (ret < 0)
+ break;
+
+ ret = check_content_type(line);
+ if (!ret)
+ return AVPROBE_SCORE_MAX;
+ }
+
+ return 0;
+}
+
+static int mpjpeg_read_header(AVFormatContext *s)
+{
+ AVStream *st;
+ char boundary[70 + 2 + 1];
+ int ret;
+
+ ret = get_line(s->pb, boundary, sizeof(boundary));
+ if (ret < 0)
+ return ret;
+
+ if (strncmp(boundary, "--", 2))
+ return AVERROR_INVALIDDATA;
+
+ st = avformat_new_stream(s, NULL);
+
+ st->codec->codec_type = AVMEDIA_TYPE_VIDEO;
+ st->codec->codec_id = AV_CODEC_ID_MJPEG;
+
+ avpriv_set_pts_info(st, 60, 1, 25);
+
+ return 0;
+}
+
+static int parse_content_length(char *line)
+{
+ char *tag, *value;
+ int ret = split_tag_value(&tag, &value, line);
+ long int val;
+
+ if (ret < 0)
+ return ret;
+
+ if (av_strcasecmp(tag, "Content-Length"))
+ return AVERROR_INVALIDDATA;
+
+ val = strtol(value, NULL, 10);
+ if (val == LONG_MIN || val == LONG_MAX)
+ return AVERROR(errno);
+ if (val > INT_MAX)
+ return AVERROR(ERANGE);
+ return val;
+}
+
+static int mpjpeg_read_packet(AVFormatContext *s, AVPacket *pkt)
+{
+ char line[128];
+ int ret, size;
+
+ ret = get_line(s->pb, line, sizeof(line));
+ if (ret < 0)
+ return ret;
+
+ ret = check_content_type(line);
+ if (ret < 0)
+ return ret;
+
+ ret = get_line(s->pb, line, sizeof(line));
+ if (ret < 0)
+ return ret;
+
+ size = parse_content_length(line);
+ if (size < 0)
+ return size;
+ // Consume empty line
+ ret = get_line(s->pb, line, sizeof(line));
+ if (ret < 0)
+ goto fail;
+
+ ret = av_new_packet(pkt, size);
+ if (ret < 0)
+ return ret;
+
+ ret = avio_read(s->pb, pkt->data, size);
+ if (ret < 0)
+ goto fail;
+
+ // Consume the boundary marker
+ ret = get_line(s->pb, line, sizeof(line));
+ if (ret < 0)
+ goto fail;
+ ret = get_line(s->pb, line, sizeof(line));
+ if (ret < 0)
+ goto fail;
+
+ return ret;
+
+fail:
+ av_free_packet(pkt);
+ return ret;
+}
+
+AVInputFormat ff_mpjpeg_demuxer = {
+ .name = "mpjpeg",
+ .long_name = NULL_IF_CONFIG_SMALL("MIME multipart JPEG"),
+ .mime_type = "multipart/x-mixed-replace",
+ .extensions = "mjpg",
+ .read_probe = mpjpeg_read_probe,
+ .read_header = mpjpeg_read_header,
+ .read_packet = mpjpeg_read_packet,
+};
--
2.1.0
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