Add RTP packetization of Theora and Vorbis

Patch by Josh Allmann, joshua dot allmann at gmail

Originally committed as revision 24735 to svn://svn.ffmpeg.org/ffmpeg/trunk

1 files changed, 125 insertions, 0 deletions

diff --git a/libavformat/rtpenc_xiph.c b/libavformat/rtpenc_xiph.c
new file mode 100644
index 0000000000..4899abb13e
--- /dev/null
+++ b/libavformat/rtpenc_xiph.c
@@ -0,0 +1,125 @@
+/*
+ * RTP packetization for Xiph audio and video
+ * Copyright (c) 2010 Josh Allmann
+ *
+ * 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 "rtpenc.h"
+
+/**
+ * Packetize Xiph frames into RTP according to
+ * RFC 5215 (Vorbis) and the Theora RFC draft.
+ * (http://svn.xiph.org/trunk/theora/doc/draft-ietf-avt-rtp-theora-00.txt)
+ */
+void ff_rtp_send_xiph(AVFormatContext *s1, const uint8_t *buff, int size)
+{
+    RTPMuxContext *s = s1->priv_data;
+    int max_pkt_size, xdt, frag;
+    uint8_t *q;
+
+    max_pkt_size = s->max_payload_size;
+
+    // set xiph data type
+    switch (*buff) {
+    case 0x01:   // vorbis id
+    case 0x05:   // vorbis setup
+    case 0x80:   // theora header
+    case 0x82:   // theora tables
+        xdt = 1; // packed config payload
+        break;
+    case 0x03:   // vorbis comments
+    case 0x81:   // theora comments
+        xdt = 2; // comment payload
+        break;
+    default:
+        xdt = 0; // raw data payload
+        break;
+    }
+
+    // Set ident. Must match the one in sdp.c
+    // Probably need a non-fixed way of generating
+    // this, but it has to be done in SDP and passed in from there.
+    q = s->buf;
+    *q++ = 0xfe;
+    *q++ = 0xcd;
+    *q++ = 0xba;
+
+    // set fragment
+    // 0 - whole frame (possibly multiple frames)
+    // 1 - first fragment
+    // 2 - fragment continuation
+    // 3 - last fragmement
+    frag = size <= max_pkt_size ? 0 : 1;
+
+    if (!frag && !xdt) { // do we have a whole frame of raw data?
+        unsigned end_ptr = (unsigned)s->buf + 6 + max_pkt_size; // what we're allowed to write
+        unsigned ptr     = (unsigned)s->buf_ptr + 2 + size; // what we're going to write
+        int remaining    = end_ptr - ptr;
+
+        if ((s->num_frames > 0 && remaining < 0) ||
+            s->num_frames >= s->max_frames_per_packet) {
+            // send previous packets now; no room for new data
+            ff_rtp_send_data(s1, s->buf, s->buf_ptr - s->buf, 0);
+            s->num_frames = 0;
+        }
+
+        // buffer current frame to send later
+        if (0 == s->num_frames) s->timestamp = s->cur_timestamp;
+        s->num_frames++;
+
+        // Set packet header. Normally, this is OR'd with frag and xdt,
+        // but those are zero, so omitted here
+        *q++ = s->num_frames;
+
+        if (s->num_frames > 1) q = s->buf_ptr; // jump ahead if needed
+        *q++ = (size >> 8) & 0xff;
+        *q++ = size & 0xff;
+        memcpy(q, buff, size);
+        q += size;
+        s->buf_ptr = q;
+
+        return;
+    } else if (s->num_frames) {
+        // immediately send buffered frames if buffer is not raw data,
+        // or if current frame is fragmented.
+        ff_rtp_send_data(s1, s->buf, s->buf_ptr - s->buf, 0);
+    }
+
+    s->timestamp = s->cur_timestamp;
+    s->num_frames = 0;
+    s->buf_ptr = q;
+    while (size > 0) {
+        int len = (!frag || frag == 3) ? size : max_pkt_size;
+        q = s->buf_ptr;
+
+        // set packet headers
+        *q++ = (frag << 6) | (xdt << 4); // num_frames = 0
+        *q++ = (len >> 8) & 0xff;
+        *q++ = len & 0xff;
+        // set packet body
+        memcpy(q, buff, len);
+        q += len;
+        buff += len;
+        size -= len;
+
+        ff_rtp_send_data(s1, s->buf, q - s->buf, 0);
+
+        frag = size <= max_pkt_size ? 3 : 2;
+    }
+}