Add dynamic payload handlers to rdt.c. These follow the same API as the ones

in rtpdec.c, so that they can be shared and used in the same way in rtsp.c.
The handlers, since they are specific for RDT, are registered in rdt.c and
a new registration function is thus called from allformats.c.

The dynamic payload handler also implements RDT-specific SDP-line parsing for
OpaqueData and StartTime, which are specific for RDT and needed for proper
playback. OpaqueData contains one or a list ("MLTI") of "MDPR" chunks that
can be parsed by the rmdec.c function ff_rm_read_mdpr_codecdata(). To use
this function, we create a new rdt_demuxer, which has the same private data
as the rm_demuxer. The resulting AVFormatContext created with _open_stream()
can thus be used to call functions in the RM demuxer.

See discussion in "Realmedia patch" thread on ML.

Originally committed as revision 15234 to svn://svn.ffmpeg.org/ffmpeg/trunk

1 files changed, 136 insertions, 0 deletions

diff --git a/libavformat/rdt.c b/libavformat/rdt.c
index 1d0e4559d0..e5a1f89c6d 100644
--- a/libavformat/rdt.c
+++ b/libavformat/rdt.c
@@ -27,12 +27,19 @@
 
 #include "avformat.h"
 #include "libavutil/avstring.h"
+#include "rtp_internal.h"
 #include "rdt.h"
 #include "libavutil/base64.h"
 #include "libavutil/md5.h"
 #include "rm.h"
 #include "internal.h"
 
+typedef struct rdt_data {
+    AVFormatContext *rmctx;
+    uint8_t *mlti_data;
+    unsigned int mlti_data_size;
+} rdt_data;
+
 void
 ff_rdt_calc_response_and_checksum(char response[41], char chksum[9],
                                   const char *challenge)
@@ -71,3 +78,132 @@ ff_rdt_calc_response_and_checksum(char response[41], char chksum[9],
         chksum[i] = response[i * 4];
     chksum[8] = 0;
 }
+
+static int
+rdt_load_mdpr (rdt_data *rdt, AVStream *st, int rule_nr)
+{
+    ByteIOContext *pb;
+    int size;
+    uint32_t tag;
+
+    /**
+     * Layout of the MLTI chunk:
+     * 4:MLTI
+     * 2:<number of streams>
+     * Then for each stream ([number_of_streams] times):
+     *     2:<mdpr index>
+     * 2:<number of mdpr chunks>
+     * Then for each mdpr chunk ([number_of_mdpr_chunks] times):
+     *     4:<size>
+     *     [size]:<data>
+     * we skip MDPR chunks until we reach the one of the stream
+     * we're interested in, and forward that ([size]+[data]) to
+     * the RM demuxer to parse the stream-specific header data.
+     */
+    if (!rdt->mlti_data)
+        return -1;
+    url_open_buf(&pb, rdt->mlti_data, rdt->mlti_data_size, URL_RDONLY);
+    tag = get_le32(pb);
+    if (tag == MKTAG('M', 'L', 'T', 'I')) {
+        int num, chunk_nr;
+
+        /* read index of MDPR chunk numbers */
+        num = get_be16(pb);
+        if (rule_nr < 0 || rule_nr >= num)
+            return -1;
+        url_fskip(pb, rule_nr * 2);
+        chunk_nr = get_be16(pb);
+        url_fskip(pb, (num - 1 - rule_nr) * 2);
+
+        /* read MDPR chunks */
+        num = get_be16(pb);
+        if (chunk_nr >= num)
+            return -1;
+        while (chunk_nr--)
+            url_fskip(pb, get_be32(pb));
+        size = get_be32(pb);
+    } else {
+        size = rdt->mlti_data_size;
+        url_fseek(pb, 0, SEEK_SET);
+    }
+    rdt->rmctx->pb = pb;
+    if (ff_rm_read_mdpr_codecdata(rdt->rmctx, st, size) < 0)
+        return -1;
+
+    url_close_buf(pb);
+    return 0;
+}
+
+static unsigned char *
+rdt_parse_b64buf (unsigned int *target_len, const char *p)
+{
+    unsigned char *target;
+    int len = strlen(p);
+    if (*p == '\"') {
+        p++;
+        len -= 2; /* skip embracing " at start/end */
+    }
+    *target_len = len * 3 / 4;
+    target = av_mallocz(*target_len + FF_INPUT_BUFFER_PADDING_SIZE);
+    av_base64_decode(target, p, *target_len);
+    return target;
+}
+
+static int
+rdt_parse_sdp_line (AVStream *stream, void *d, const char *line)
+{
+    rdt_data *rdt = d;
+    const char *p = line;
+
+    if (av_strstart(p, "OpaqueData:buffer;", &p)) {
+        rdt->mlti_data = rdt_parse_b64buf(&rdt->mlti_data_size, p);
+        rdt_load_mdpr(rdt, stream, 0);
+    } else if (av_strstart(p, "StartTime:integer;", &p))
+        stream->first_dts = atoi(p);
+
+    return 0;
+}
+
+static void *
+rdt_new_extradata (void)
+{
+    rdt_data *rdt = av_mallocz(sizeof(rdt_data));
+
+    av_open_input_stream(&rdt->rmctx, NULL, "", &rdt_demuxer, NULL);
+
+    return rdt;
+}
+
+static void
+rdt_free_extradata (void *d)
+{
+    rdt_data *rdt = d;
+
+    if (rdt->rmctx)
+        av_close_input_stream(rdt->rmctx);
+    av_freep(&rdt->mlti_data);
+    av_free(rdt);
+}
+
+#define RDT_HANDLER(n, s, t) \
+static RTPDynamicProtocolHandler ff_rdt_ ## n ## _handler = { \
+    s, \
+    t, \
+    CODEC_ID_NONE, \
+    rdt_parse_sdp_line, \
+    rdt_new_extradata, \
+    rdt_free_extradata \
+};
+
+RDT_HANDLER(live_video, "x-pn-multirate-realvideo-live", CODEC_TYPE_VIDEO);
+RDT_HANDLER(live_audio, "x-pn-multirate-realaudio-live", CODEC_TYPE_AUDIO);
+RDT_HANDLER(video,      "x-pn-realvideo",                CODEC_TYPE_VIDEO);
+RDT_HANDLER(audio,      "x-pn-realaudio",                CODEC_TYPE_AUDIO);
+
+void av_register_rdt_dynamic_payload_handlers(void)
+{
+    ff_register_dynamic_payload_handler(&ff_rdt_video_handler);
+    ff_register_dynamic_payload_handler(&ff_rdt_audio_handler);
+    ff_register_dynamic_payload_handler(&ff_rdt_live_video_handler);
+    ff_register_dynamic_payload_handler(&ff_rdt_live_audio_handler);
+}