NC camera demuxer

Patch by Nicolas Martin - elvadrias at gmail

Originally committed as revision 17062 to svn://svn.ffmpeg.org/ffmpeg/trunk

1 files changed, 100 insertions, 0 deletions

diff --git a/libavformat/ncdec.c b/libavformat/ncdec.c
new file mode 100644
index 0000000000..e6cca1068b
--- /dev/null
+++ b/libavformat/ncdec.c
@@ -0,0 +1,100 @@
+/*
+ * NC camera feed demuxer
+ * Copyright (c) 2009  Nicolas Martin (martinic at iro dot umontreal dot ca)
+ *                     Edouard Auvinet
+ *
+ * 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
+ */
+
+#include "libavutil/intreadwrite.h"
+#include "avformat.h"
+
+#define NC_VIDEO_FLAG 0x1A5
+
+static int nc_probe(AVProbeData *probe_packet)
+{
+    int size;
+
+    if (AV_RB32(probe_packet->buf) != NC_VIDEO_FLAG)
+        return 0;
+
+    size = AV_RL16(probe_packet->buf + 5);
+
+    if (size + 20 > probe_packet->buf_size)
+        return 3*AVPROBE_SCORE_MAX/2;
+
+    if (AV_RB32(probe_packet->buf+16+size) == NC_VIDEO_FLAG)
+        return AVPROBE_SCORE_MAX;
+
+    return 0;
+}
+
+static int nc_read_header(AVFormatContext *s, AVFormatParameters *ap)
+{
+    AVStream *st = av_new_stream(s, 0);
+
+    if (!st)
+        return AVERROR(ENOMEM);
+
+    st->codec->codec_type = CODEC_TYPE_VIDEO;
+    st->codec->codec_id   = CODEC_ID_MPEG4;
+    st->need_parsing      = AVSTREAM_PARSE_FULL;
+
+    av_set_pts_info(st, 64, 1, 100);
+
+    return 0;
+}
+
+static int nc_read_packet(AVFormatContext *s, AVPacket *pkt)
+{
+    int size;
+
+    uint32_t state=-1;
+    while (state != NC_VIDEO_FLAG) {
+        if (url_feof(s->pb))
+            return AVERROR(EIO);
+        state = (state<<8) + get_byte(s->pb);
+    }
+
+    get_byte(s->pb);
+    size = get_le16(s->pb);
+    url_fskip(s->pb, 9);
+
+    if (size == 0) {
+        av_log(s, AV_LOG_DEBUG, "Next packet size is zero\n");
+        return AVERROR(EAGAIN);
+    }
+
+    int ret = av_get_packet(s->pb, pkt, size);
+    if (ret != size) {
+        if (ret > 0) av_free_packet(pkt);
+        return AVERROR(EIO);
+    }
+
+    pkt->stream_index = 0;
+    return size;
+}
+
+AVInputFormat nc_demuxer = {
+    "nc",
+    NULL_IF_CONFIG_SMALL("NC camera feed format"),
+    0,
+    nc_probe,
+    nc_read_header,
+    nc_read_packet,
+    .extensions = "v",
+};