MSN TCP Webcam stream demuxer.

Originally committed as revision 12492 to svn://svn.ffmpeg.org/ffmpeg/trunk
2025-08-06 15:49:50 +08:00 · 2008-03-18 19:54:47 +00:00
parent a7129de51b
commit 0f3444e17c
6 changed files with 145 additions and 1 deletions
--- a/libavformat/msnwc_tcp.c
+++ b/libavformat/msnwc_tcp.c
@ -0,0 +1,140 @@
+/*
+ * Copyright (C) 2008  Ramiro Polla <ramiro@lisha.ufsc.br>
+ *
+ * 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 "avformat.h"
+#include "bytestream.h"
+
+#define HEADER_SIZE         24
+
+/*
+ * Header structure:
+ *  uint16_t    ss;     // struct size
+ *  uint16_t    width;  // frame width
+ *  uint16_t    height; // frame height
+ *  uint16_t    ff;     // keyframe + some other info(???)
+ *  uint32_t    size;   // size of data
+ *  uint32_t    fourcc; // ML20
+ *  uint32_t    u3;     // ?
+ *  uint32_t    ts;     // time
+ */
+
+static int msnwc_tcp_probe(AVProbeData *p)
+{
+    int i;
+
+    for(i = 0 ; i + HEADER_SIZE <= p->buf_size ; i++) {
+        uint16_t width, height;
+        uint32_t fourcc;
+        const uint8_t *bytestream = p->buf+i;
+
+        if(bytestream_get_le16(&bytestream) != HEADER_SIZE)
+            continue;
+        width  = bytestream_get_le16(&bytestream);
+        height = bytestream_get_le16(&bytestream);
+        if(!(width==320 && height==240) && !(width==160 && height==120))
+            continue;
+        bytestream += 2; // keyframe
+        bytestream += 4; // size
+        fourcc = bytestream_get_le32(&bytestream);
+        if(fourcc != MKTAG('M', 'L', '2', '0'))
+            continue;
+
+        if(i) {
+            if(i < 14)  /* starts with SwitchBoard connection info */
+                return AVPROBE_SCORE_MAX / 2;
+            else        /* starts in the middle of stream */
+                return AVPROBE_SCORE_MAX / 3;
+        } else {
+            return AVPROBE_SCORE_MAX;
+        }
+    }
+
+    return -1;
+}
+
+static int msnwc_tcp_read_header(AVFormatContext *ctx, AVFormatParameters *ap)
+{
+    ByteIOContext *pb = ctx->pb;
+    AVCodecContext *codec;
+    AVStream *st;
+
+    st = av_new_stream(ctx, 0);
+    if(!st)
+        return AVERROR_NOMEM;
+
+    codec = st->codec;
+    codec->codec_type = CODEC_TYPE_VIDEO;
+    codec->codec_id = CODEC_ID_MIMIC;
+    codec->codec_tag = MKTAG('M', 'L', '2', '0');
+
+    av_set_pts_info(st, 32, 1, 1000);
+
+    /* Some files start with "connected\r\n\r\n".
+     * So skip until we find the first byte of struct size */
+    while(get_byte(pb) != HEADER_SIZE && !url_feof(pb));
+
+    if(url_feof(pb)) {
+        av_log(ctx, AV_LOG_ERROR, "Could not find valid start.");
+        return -1;
+    }
+
+    return 0;
+}
+
+static int msnwc_tcp_read_packet(AVFormatContext *ctx, AVPacket *pkt)
+{
+    ByteIOContext *pb = ctx->pb;
+    uint16_t keyframe;
+    uint32_t size, timestamp;
+
+    url_fskip(pb, 1); /* one byte has been read ahead */
+    url_fskip(pb, 2);
+    url_fskip(pb, 2);
+    keyframe = get_le16(pb);
+    size = get_le32(pb);
+    url_fskip(pb, 4);
+    url_fskip(pb, 4);
+    timestamp = get_le32(pb);
+
+    if(!size || av_get_packet(pb, pkt, size) != size)
+        return -1;
+
+    url_fskip(pb, 1); /* Read ahead one byte of struct size like read_header */
+
+    pkt->pts = timestamp;
+    pkt->dts = timestamp;
+    pkt->stream_index = 0;
+
+    /* Some aMsn generated videos (or was it Mercury Messenger?) don't set
+     * this bit and rely on the codec to get keyframe information */
+    if(keyframe&1)
+        pkt->flags |= PKT_FLAG_KEY;
+
+    return HEADER_SIZE + size;
+}
+
+AVInputFormat msnwc_tcp_demuxer = {
+    "msnwctcp",
+    "MSN TCP Webcam stream",
+    0,
+    msnwc_tcp_probe,
+    msnwc_tcp_read_header,
+    msnwc_tcp_read_packet,
+};