mpjpeg: Initial implementation

Support only streams with Content-Length.
Signed-off-by: Luca Barbato <lu_zero@gentoo.org>

Changelog

@@ -32,6 +32,7 @@ version <next>:
 - Automatically rotate videos based on metadata in avconv
 - improved Quickdraw compatibility
 - NVIDIA NVENC-accelerated H.264 and HEVC encoding support
+- Multipart JPEG demuxer
 
 
 version 11:

libavformat/Makefile

@@ -205,6 +205,7 @@ 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

libavformat/allformats.c

@@ -163,7 +163,7 @@ 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);

libavformat/mpjpegdec.c

+/*
+ * Multipart JPEG format
+ * Copyright (c) 2015 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 = ff_get_line(pb, line, line_size);
+
+    if (i > 1 && line[i - 2] == '\r')
+        line[i - 2] = '\0';
+
+    if (pb->error)
+        return pb->error;
+
+    if (pb->eof_reached)
+        return AVERROR_EOF;
+
+    return 0;
+}
+
+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 = 0;
+
+    pb = avio_alloc_context(p->buf, p->buf_size, 0, NULL, NULL, NULL, NULL);
+    if (!pb)
+        return AVERROR(ENOMEM);
+
+    if (p->buf_size < 2 || p->buf[0] != '-' || p->buf[1] != '-')
+        return 0;
+
+    while (!pb->eof_reached) {
+        ret = get_line(pb, line, sizeof(line));
+        if (ret < 0)
+            break;
+
+        ret = check_content_type(line);
+        if (!ret) {
+            ret = AVPROBE_SCORE_MAX;
+            break;
+        }
+    }
+
+    av_free(pb);
+
+    return ret;
+}
+
+static int mpjpeg_read_header(AVFormatContext *s)
+{
+    AVStream *st;
+    char boundary[70 + 2 + 1];
+    int64_t pos = avio_tell(s->pb);
+    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);
+
+    avio_seek(s->pb, pos, SEEK_SET);
+
+    return 0;
+}
+
+static int parse_content_length(const char *value)
+{
+    long int 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 parse_multipart_header(AVFormatContext *s)
+{
+    char line[128];
+    int found_content_type = 0;
+    int ret, size = -1;
+
+    ret = get_line(s->pb, line, sizeof(line));
+    if (ret < 0)
+        return ret;
+
+    if (strncmp(line, "--", 2))
+        return AVERROR_INVALIDDATA;
+
+    while (!s->pb->eof_reached) {
+        char *tag, *value;
+
+        ret = get_line(s->pb, line, sizeof(line));
+        if (ret < 0)
+            return ret;
+
+        if (line[0] == '\0')
+            break;
+
+        ret = split_tag_value(&tag, &value, line);
+        if (ret < 0)
+            return ret;
+
+        if (!av_strcasecmp(tag, "Content-type")) {
+            if (av_strcasecmp(value, "image/jpeg")) {
+                av_log(s, AV_LOG_ERROR,
+                       "Unexpected %s : %s\n",
+                       tag, value);
+                return AVERROR_INVALIDDATA;
+            } else
+                found_content_type = 1;
+        } else if (!av_strcasecmp(tag, "Content-Length")) {
+            size = parse_content_length(value);
+            if (size < 0)
+                return size;
+        }
+    }
+
+    if (!found_content_type || size < 0) {
+        return AVERROR_INVALIDDATA;
+    }
+
+    return size;
+}
+
+static int mpjpeg_read_packet(AVFormatContext *s, AVPacket *pkt)
+{
+    int ret;
+    int size = parse_multipart_header(s);
+
+    if (size < 0)
+        return size;
+
+    ret = av_get_packet(s->pb, pkt, size);
+    if (ret < 0)
+        return ret;
+
+    // trailing empty line
+    avio_skip(s->pb, 2);
+
+    return 0;
+}
+
+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,
+};

libavformat/version.h

@@ -30,7 +30,7 @@
 #include "libavutil/version.h"
 
 #define LIBAVFORMAT_VERSION_MAJOR 56
-#define LIBAVFORMAT_VERSION_MINOR 18
+#define LIBAVFORMAT_VERSION_MINOR 19
 #define LIBAVFORMAT_VERSION_MICRO  0
 
 #define LIBAVFORMAT_VERSION_INT AV_VERSION_INT(LIBAVFORMAT_VERSION_MAJOR, \