Add RTP/H.263 depacketizer by Martin Storsjö <$firstname () $firstname st>.

Originally committed as revision 21512 to svn://svn.ffmpeg.org/ffmpeg/trunk

1 files changed, 108 insertions, 0 deletions

diff --git a/libavformat/rtpdec_h263.c b/libavformat/rtpdec_h263.c
new file mode 100644
index 0000000000..7d498f3af0
--- /dev/null
+++ b/libavformat/rtpdec_h263.c
@@ -0,0 +1,108 @@
+/*
+ * RTP H.263 Depacketizer, RFC 4629
+ * Copyright (c) 2010 Martin Storsjo
+ *
+ * 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 "rtpdec_h263.h"
+#include "libavutil/intreadwrite.h"
+
+static int h263_handle_packet(AVFormatContext *ctx,
+                              PayloadContext *data,
+                              AVStream *st,
+                              AVPacket * pkt,
+                              uint32_t * timestamp,
+                              const uint8_t * buf,
+                              int len, int flags)
+{
+    uint8_t *ptr;
+    uint16_t header;
+    int startcode, vrc, picture_header;
+
+    if (len < 2) {
+        av_log(ctx, AV_LOG_ERROR, "Too short H.263 RTP packet\n");
+        return AVERROR_INVALIDDATA;
+    }
+
+    /* Decode the 16 bit H.263+ payload header, as described in section
+     * 5.1 of RFC 4629. The fields of this header are:
+     * - 5 reserved bits, should be ignored.
+     * - One bit (P, startcode), indicating a picture start, picture segment
+     *   start or video sequence end. If set, two zero bytes should be
+     *   prepended to the payload.
+     * - One bit (V, vrc), indicating the presence of an 8 bit Video
+     *   Redundancy Coding field after this 16 bit header.
+     * - 6 bits (PLEN, picture_header), the length (in bytes) of an extra
+     *   picture header, following the VRC field.
+     * - 3 bits (PEBIT), the number of bits to ignore of the last byte
+     *   of the extra picture header. (Not used at the moment.)
+     */
+    header = AV_RB16(buf);
+    startcode      = (header & 0x0400) >> 9;
+    vrc            =  header & 0x0200;
+    picture_header = (header & 0x01f8) >> 3;
+    buf += 2;
+    len -= 2;
+
+    if (vrc) {
+        /* Skip VRC header if present, not used at the moment. */
+        buf += 1;
+        len -= 1;
+    }
+    if (picture_header) {
+        /* Skip extra picture header if present, not used at the moment. */
+        buf += picture_header;
+        len -= picture_header;
+    }
+
+    if (len < 0) {
+        av_log(ctx, AV_LOG_ERROR, "Too short H.263 RTP packet\n");
+        return AVERROR_INVALIDDATA;
+    }
+
+    if (av_new_packet(pkt, len + startcode)) {
+        av_log(ctx, AV_LOG_ERROR, "Out of memory\n");
+        return AVERROR_NOMEM;
+    }
+    pkt->stream_index = st->index;
+    ptr = pkt->data;
+
+    if (startcode) {
+        *ptr++ = 0;
+        *ptr++ = 0;
+    }
+    memcpy(ptr, buf, len);
+
+    return 0;
+}
+
+RTPDynamicProtocolHandler ff_h263_1998_dynamic_handler = {
+    .enc_name         = "H263-1998",
+    .codec_type       = CODEC_TYPE_VIDEO,
+    .codec_id         = CODEC_ID_H263,
+    .parse_packet     = h263_handle_packet,
+};
+
+RTPDynamicProtocolHandler ff_h263_2000_dynamic_handler = {
+    .enc_name         = "H263-2000",
+    .codec_type       = CODEC_TYPE_VIDEO,
+    .codec_id         = CODEC_ID_H263,
+    .parse_packet     = h263_handle_packet,
+};
+