MMS-over-TCP protocol support. Patch by Zhentan Feng <spyfeng gmail com>.

Originally committed as revision 23301 to svn://svn.ffmpeg.org/ffmpeg/trunk

1 files changed, 690 insertions, 0 deletions

diff --git a/libavformat/mmst.c b/libavformat/mmst.c
new file mode 100644
index 0000000000..9b2e497c3c
--- /dev/null
+++ b/libavformat/mmst.c
@@ -0,0 +1,690 @@
+/*
+ * MMS protocol over TCP
+ * Copyright (c) 2006,2007 Ryan Martell
+ * Copyright (c) 2007 Björn Axelsson
+ * Copyright (c) 2010 Zhentan Feng <spyfeng at gmail dot com>
+ *
+ * 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 "internal.h"
+#include "libavutil/intreadwrite.h"
+#include "libavcodec/bytestream.h"
+#include "network.h"
+#include "asf.h"
+
+#define LOCAL_ADDRESS 0xc0a80081    // FIXME get and use correct local ip address.
+#define LOCAL_PORT    1037          // as above.
+/** Client to server packet types. */
+typedef enum {
+    CS_PKT_INITIAL                  = 0x01,
+    CS_PKT_PROTOCOL_SELECT          = 0x02,
+    CS_PKT_MEDIA_FILE_REQUEST       = 0x05,
+    CS_PKT_START_FROM_PKT_ID        = 0x07,
+    CS_PKT_STREAM_PAUSE             = 0x09,
+    CS_PKT_STREAM_CLOSE             = 0x0d,
+    CS_PKT_MEDIA_HEADER_REQUEST     = 0x15,
+    CS_PKT_TIMING_DATA_REQUEST      = 0x18,
+    CS_PKT_USER_PASSWORD            = 0x1a,
+    CS_PKT_KEEPALIVE                = 0x1b,
+    CS_PKT_STREAM_ID_REQUEST        = 0x33,
+} MMSCSPacketType;
+
+/** Server to client packet types. */
+typedef enum {
+    /** Control packets. */
+    /*@{*/
+    SC_PKT_CLIENT_ACCEPTED          = 0x01,
+    SC_PKT_PROTOCOL_ACCEPTED        = 0x02,
+    SC_PKT_PROTOCOL_FAILED          = 0x03,
+    SC_PKT_MEDIA_PKT_FOLLOWS        = 0x05,
+    SC_PKT_MEDIA_FILE_DETAILS       = 0x06,
+    SC_PKT_HEADER_REQUEST_ACCEPTED  = 0x11,
+    SC_PKT_TIMING_TEST_REPLY        = 0x15,
+    SC_PKT_PASSWORD_REQUIRED        = 0x1a,
+    SC_PKT_KEEPALIVE                = 0x1b,
+    SC_PKT_STREAM_STOPPED           = 0x1e,
+    SC_PKT_STREAM_CHANGING          = 0x20,
+    SC_PKT_STREAM_ID_ACCEPTED       = 0x21,
+    /*@}*/
+
+    /** Pseudo packets. */
+    /*@{*/
+    SC_PKT_CANCEL                   = -1,
+    SC_PKT_NO_DATA                  = -2,
+    /*@}*/
+
+    /** Data packets. */
+    /*@{*/
+    SC_PKT_ASF_HEADER               = 0x010000,// make it bigger than 0xFF in case of
+    SC_PKT_ASF_MEDIA                = 0x010001,// receiving false data packets.
+    /*@}*/
+} MMSSCPacketType;
+
+typedef struct {
+    int id;
+}MMSStream;
+
+typedef struct {
+    int outgoing_packet_seq;             ///< Outgoing packet sequence number.
+    char path[256];                      ///< Path of the resource being asked for.
+    char host[128];                      ///< Host of the resources.
+
+    URLContext *mms_hd;                  ///< TCP connection handle
+    MMSStream streams[MAX_STREAMS];
+
+    /** Buffer for outgoing packets. */
+    /*@{*/
+    uint8_t *write_out_ptr;              ///< Pointer for writting the buffer.
+    uint8_t out_buffer[512];             ///< Buffer for outgoing packet.
+    /*@}*/
+
+    /** Buffer for incoming packets. */
+    /*@{*/
+    uint8_t in_buffer[8192];             ///< Buffer for incoming packets.
+    uint8_t *read_in_ptr;                ///< Pointer for reading from incoming buffer.
+    int remaining_in_len;                ///< Reading length from incoming buffer.
+    /*@}*/
+
+    int incoming_packet_seq;             ///< Incoming packet sequence number.
+    int incoming_flags;                  ///< Incoming packet flags.
+
+    int packet_id;                       ///< Identifier for packets in the current stream.
+    unsigned int header_packet_id;       ///< default is 2.
+
+    /** Internal handling of the ASF header */
+    /*@{*/
+    uint8_t *asf_header;                 ///< Stored ASF header.
+    int asf_header_size;                 ///< Size of stored ASF header.
+    int header_parsed;                   ///< The header has been received and parsed.
+    int asf_packet_len;
+    /*@}*/
+
+    int stream_num;                      ///< stream numbers.
+    int is_playing;
+} MMSContext;
+
+/** Create MMST command packet header */
+static void start_command_packet(MMSContext *mms, MMSCSPacketType packet_type)
+{
+    mms->write_out_ptr = mms->out_buffer;
+
+    bytestream_put_le32(&mms->write_out_ptr, 1); // start sequence
+    bytestream_put_le32(&mms->write_out_ptr, 0xb00bface);
+    bytestream_put_le32(&mms->write_out_ptr, 0); // Length starts from after the protocol type bytes
+    bytestream_put_le32(&mms->write_out_ptr, MKTAG('M','M','S',' '));
+    bytestream_put_le32(&mms->write_out_ptr, 0);
+    bytestream_put_le32(&mms->write_out_ptr, mms->outgoing_packet_seq++);
+    bytestream_put_le64(&mms->write_out_ptr, 0); // timestamp
+    bytestream_put_le32(&mms->write_out_ptr, 0);
+    bytestream_put_le16(&mms->write_out_ptr, packet_type);
+    bytestream_put_le16(&mms->write_out_ptr, 3); // direction to server
+}
+
+/** Add prefixes to MMST command packet. */
+static void insert_command_prefixes(MMSContext *mms,
+        uint32_t prefix1, uint32_t prefix2)
+{
+    bytestream_put_le32(&mms->write_out_ptr, prefix1); // first prefix
+    bytestream_put_le32(&mms->write_out_ptr, prefix2); // second prefix
+}
+
+/** Send a prepared MMST command packet. */
+static int send_command_packet(MMSContext *mms)
+{
+    int exact_length= mms->write_out_ptr - mms->out_buffer;
+    int first_length= exact_length - 16;
+    int len8= first_length/8;
+    int write_result;
+
+    // update packet length fields.
+    AV_WL32(mms->out_buffer + 8, first_length);
+    AV_WL32(mms->out_buffer + 16, len8);
+    AV_WL32(mms->out_buffer + 32, len8-2);
+
+    // write it out.
+    write_result= url_write(mms->mms_hd, mms->out_buffer, exact_length);
+    if(write_result != exact_length) {
+        dprintf(NULL, "url_write returned: %d != %d\n",
+                write_result, exact_length);
+        return AVERROR_IO;
+    }
+
+    return 0;
+}
+
+static void mms_put_utf16(MMSContext *mms, uint8_t *src)
+{
+    ByteIOContext bic;
+    int size = mms->write_out_ptr - mms->out_buffer;
+    int len;
+    init_put_byte(&bic, mms->write_out_ptr,
+            sizeof(mms->out_buffer) - size, 1, NULL, NULL, NULL, NULL);
+
+    len = ff_put_str16_nolen(&bic, src);
+    mms->write_out_ptr += len;
+}
+
+static int send_protocol_select(MMSContext *mms)
+{
+    char data_string[256];
+
+    start_command_packet(mms, CS_PKT_PROTOCOL_SELECT);
+    insert_command_prefixes(mms, 0, 0xffffffff);
+    bytestream_put_le32(&mms->write_out_ptr, 0);          // maxFunnelBytes
+    bytestream_put_le32(&mms->write_out_ptr, 0x00989680); // maxbitRate
+    bytestream_put_le32(&mms->write_out_ptr, 2);          // funnelMode
+    snprintf(data_string, sizeof(data_string), "\\\\%d.%d.%d.%d\\%s\\%d",
+            (LOCAL_ADDRESS>>24)&0xff,
+            (LOCAL_ADDRESS>>16)&0xff,
+            (LOCAL_ADDRESS>>8)&0xff,
+            LOCAL_ADDRESS&0xff,
+            "TCP",                                        // or UDP
+            LOCAL_PORT);
+
+    mms_put_utf16(mms, data_string);
+    return send_command_packet(mms);
+}
+
+static int send_media_file_request(MMSContext *mms)
+{
+    start_command_packet(mms, CS_PKT_MEDIA_FILE_REQUEST);
+    insert_command_prefixes(mms, 1, 0xffffffff);
+    bytestream_put_le32(&mms->write_out_ptr, 0);
+    bytestream_put_le32(&mms->write_out_ptr, 0);
+    mms_put_utf16(mms, mms->path + 1); // +1 for skip "/"
+
+    return send_command_packet(mms);
+}
+
+static void handle_packet_stream_changing_type(MMSContext *mms)
+{
+    dprintf(NULL, "Stream changing!\n");
+
+    // 40 is the packet header size, 7 is the prefix size.
+    mms->header_packet_id= AV_RL32(mms->in_buffer + 40 + 7);
+    dprintf(NULL, "Changed header prefix to 0x%x", mms->header_packet_id);
+}
+
+static int send_keepalive_packet(MMSContext *mms)
+{
+    // respond to a keepalive with a keepalive...
+    start_command_packet(mms, CS_PKT_KEEPALIVE);
+    insert_command_prefixes(mms, 1, 0x100FFFF);
+    return send_command_packet(mms);
+}
+
+/** Pad media packets smaller than max_packet_size and/or adjust read position
+  * after a seek. */
+static void pad_media_packet(MMSContext *mms)
+{
+    if(mms->remaining_in_len<mms->asf_packet_len) {
+        int padding_size = mms->asf_packet_len - mms->remaining_in_len;
+        memset(mms->in_buffer + mms->remaining_in_len, 0, padding_size);
+        mms->remaining_in_len += padding_size;
+    }
+}
+
+/** Read incoming MMST media, header or command packet. */
+static MMSSCPacketType get_tcp_server_response(MMSContext *mms)
+{
+    int read_result;
+    MMSSCPacketType packet_type= -1;
+
+    for(;;) {
+        if((read_result= url_read_complete(mms->mms_hd, mms->in_buffer, 8))==8) {
+            // handle command packet.
+            if(AV_RL32(mms->in_buffer + 4)==0xb00bface) {
+                mms->incoming_flags= mms->in_buffer[3];
+                read_result= url_read_complete(mms->mms_hd, mms->in_buffer+8, 4);
+                if(read_result == 4) {
+                    int length_remaining= AV_RL32(mms->in_buffer+8) + 4;
+
+                    dprintf(NULL, "Length remaining is %d\n", length_remaining);
+                    // read the rest of the packet.
+                    if (length_remaining < 0
+                        || length_remaining > sizeof(mms->in_buffer) - 12) {
+                        dprintf("Incoming message len %d exceeds buffer len %d\n",
+                            length_remaining, sizeof(mms->in_buffer) - 12);
+                        return -1;
+                    }
+                    read_result = url_read_complete(mms->mms_hd, mms->in_buffer + 12,
+                                                  length_remaining) ;
+                    if (read_result == length_remaining) {
+                        packet_type= AV_RL16(mms->in_buffer+36);
+                    } else {
+                        dprintf(NULL, "read for packet type failed%d!\n", read_result);
+                        return -1;
+                    }
+                } else {
+                    dprintf(NULL, "read for length remaining failed%d!\n", read_result);
+                    return -1;
+                }
+            } else {
+                int length_remaining;
+                int packet_id_type;
+                int tmp;
+
+                assert(mms->remaining_in_len==0);
+
+                // note we cache the first 8 bytes,
+                // then fill up the buffer with the others
+                tmp                       = AV_RL16(mms->in_buffer + 6);
+                length_remaining          = (tmp - 8) & 0xffff;
+                mms->incoming_packet_seq  = AV_RL32(mms->in_buffer);
+                packet_id_type            = mms->in_buffer[4];
+                mms->incoming_flags       = mms->in_buffer[5];
+
+                if (length_remaining < 0
+                        || length_remaining > sizeof(mms->in_buffer) - 8) {
+                    dprintf("Incoming data len %d exceeds buffer len %d\n",
+                            length_remaining, sizeof(mms->in_buffer));
+                    return -1;
+                }
+                mms->remaining_in_len    = length_remaining;
+                mms->read_in_ptr         = mms->in_buffer;
+                read_result= url_read_complete(mms->mms_hd, mms->in_buffer, length_remaining);
+                if(read_result != length_remaining) {
+                    dprintf(NULL, "read_bytes result: %d asking for %d\n",
+                            read_result, length_remaining);
+                    return -1;
+                } else {
+                    // if we successfully read everything.
+                    if(packet_id_type == mms->header_packet_id) {
+                        packet_type = SC_PKT_ASF_HEADER;
+                        // Store the asf header
+                        if(!mms->header_parsed) {
+                            void *p = av_realloc(mms->asf_header,
+                                              mms->asf_header_size
+                                              + mms->remaining_in_len);
+                            if (!p) {
+                                av_freep(&mms->asf_header);
+                                return AVERROR(ENOMEM);
+                            }
+                            mms->asf_header = p;
+                            memcpy(mms->asf_header + mms->asf_header_size,
+                                                 mms->read_in_ptr,
+                                                 mms->remaining_in_len);
+                            mms->asf_header_size += mms->remaining_in_len;
+                        }
+                    } else if(packet_id_type == mms->packet_id) {
+                        packet_type = SC_PKT_ASF_MEDIA;
+                    } else {
+                        dprintf(NULL, "packet id type %d is old.", packet_id_type);
+                        continue;
+                    }
+                }
+            }
+
+            // preprocess some packet type
+            if(packet_type == SC_PKT_KEEPALIVE) {
+                send_keepalive_packet(mms);
+                continue;
+            } else if(packet_type == SC_PKT_STREAM_CHANGING) {
+                handle_packet_stream_changing_type(mms);
+            } else if(packet_type == SC_PKT_ASF_MEDIA) {
+                pad_media_packet(mms);
+            }
+            return packet_type;
+        } else {
+            if(read_result<0) {
+                dprintf(NULL, "Read error (or cancelled) returned %d!\n", read_result);
+                packet_type = SC_PKT_CANCEL;
+            } else {
+                dprintf(NULL, "Read result of zero?!\n");
+                packet_type = SC_PKT_NO_DATA;
+            }
+            return packet_type;
+        }
+    }
+}
+
+static int mms_safe_send_recv(MMSContext *mms,
+                              int (*send_fun)(MMSContext *mms),
+                              const MMSSCPacketType expect_type)
+{
+    MMSSCPacketType type;
+    if(send_fun) {
+        int ret = send_fun(mms);
+        if (ret < 0) {
+            dprintf(NULL, "Send Packet error before expecting recv packet %d\n", expect_type);
+            return ret;
+        }
+    }
+
+    if ((type = get_tcp_server_response(mms)) != expect_type) {
+        dprintf(NULL,"Unexpected packet type %d with type %d\n", type, expect_type);
+        return -1;
+    } else {
+        return 0;
+    }
+}
+
+static int send_media_header_request(MMSContext *mms)
+{
+    start_command_packet(mms, CS_PKT_MEDIA_HEADER_REQUEST);
+    insert_command_prefixes(mms, 1, 0);
+    bytestream_put_le32(&mms->write_out_ptr, 0);
+    bytestream_put_le32(&mms->write_out_ptr, 0x00800000);
+    bytestream_put_le32(&mms->write_out_ptr, 0xffffffff);
+    bytestream_put_le32(&mms->write_out_ptr, 0);
+    bytestream_put_le32(&mms->write_out_ptr, 0);
+    bytestream_put_le32(&mms->write_out_ptr, 0);
+
+    // the media preroll value in milliseconds?
+    bytestream_put_le32(&mms->write_out_ptr, 0);
+    bytestream_put_le32(&mms->write_out_ptr, 0x40AC2000);
+    bytestream_put_le32(&mms->write_out_ptr, 2);
+    bytestream_put_le32(&mms->write_out_ptr, 0);
+
+    return send_command_packet(mms);
+}
+
+/** Send the initial handshake. */
+static int send_startup_packet(MMSContext *mms)
+{
+    char data_string[256];
+    // SubscriberName is defined in MS specification linked below.
+    // The guid value can be any valid value.
+    // http://download.microsoft.com/
+    // download/9/5/E/95EF66AF-9026-4BB0-A41D-A4F81802D92C/%5BMS-WMSP%5D.pdf
+    snprintf(data_string, sizeof(data_string),
+            "NSPlayer/7.0.0.1956; {%s}; Host: %s",
+            "7E667F5D-A661-495E-A512-F55686DDA178", mms->host);
+
+    start_command_packet(mms, CS_PKT_INITIAL);
+    insert_command_prefixes(mms, 0, 0x0004000b);
+    bytestream_put_le32(&mms->write_out_ptr, 0x0003001c);
+    mms_put_utf16(mms, data_string);
+    return send_command_packet(mms);
+}
+
+static int asf_header_parser(MMSContext *mms)
+{
+    uint8_t *p = mms->asf_header;
+    uint8_t *end;
+    int flags, stream_id, real_header_size;
+    mms->stream_num = 0;
+
+    if (mms->asf_header_size < sizeof(ff_asf_guid) * 2 + 22 ||
+        memcmp(p, ff_asf_header, sizeof(ff_asf_guid)))
+        return -1;
+
+    real_header_size = AV_RL64(p + sizeof(ff_asf_guid));
+    end = mms->asf_header + real_header_size;
+
+    p += sizeof(ff_asf_guid) + 14;
+    while(end - p >= sizeof(ff_asf_guid) + 8) {
+        uint64_t chunksize = AV_RL64(p + sizeof(ff_asf_guid));
+        if (!chunksize || chunksize > end - p) {
+            dprintf("chunksize is exceptional value:%d!\n", chunksize);
+            return -1;
+        }
+        if (!memcmp(p, ff_asf_file_header, sizeof(ff_asf_guid))) {
+            /* read packet size */
+            if (end - p > sizeof(ff_asf_guid) * 2 + 68) {
+                mms->asf_packet_len = AV_RL32(p + sizeof(ff_asf_guid) * 2 + 64);
+                if (mms->asf_packet_len <= 0 || mms->asf_packet_len > sizeof(mms->in_buffer)) {
+                    dprintf(NULL,"Too large packet len:%d"
+                        " may overwrite in_buffer when padding", mms->asf_packet_len);
+                    return -1;
+                }
+            }
+        } else if (!memcmp(p, ff_asf_stream_header, sizeof(ff_asf_guid))) {
+            flags     = AV_RL16(p + sizeof(ff_asf_guid)*3 + 24);
+            stream_id = flags & 0x7F;
+            //The second condition is for checking CS_PKT_STREAM_ID_REQUEST packet size,
+            //we can calcuate the packet size by stream_num.
+            //Please see function send_stream_selection_request().
+            if (mms->stream_num < MAX_STREAMS &&
+                    46 + mms->stream_num * 6 < sizeof(mms->out_buffer)) {
+                mms->streams[mms->stream_num].id = stream_id;
+                mms->stream_num++;
+            } else {
+                dprintf("Too many streams.\n");
+                return -1;
+            }
+        }
+        p += chunksize;
+    }
+
+    return 0;
+}
+
+/** Send MMST stream selection command based on the AVStream->discard values. */
+static int send_stream_selection_request(MMSContext *mms)
+{
+    int i;
+
+    //  send the streams we want back...
+    start_command_packet(mms, CS_PKT_STREAM_ID_REQUEST);
+    bytestream_put_le32(&mms->write_out_ptr, mms->stream_num);         // stream nums
+    for(i= 0; i<mms->stream_num; i++) {
+        bytestream_put_le16(&mms->write_out_ptr, 0xffff);              // flags
+        bytestream_put_le16(&mms->write_out_ptr, mms->streams[i].id);  // stream id
+        bytestream_put_le16(&mms->write_out_ptr, 0);                   // selection
+    }
+
+    bytestream_put_le16(&mms->write_out_ptr, 0);
+
+    return send_command_packet(mms);
+}
+
+static int read_data(MMSContext *mms, uint8_t *buf, const int buf_size)
+{
+    int read_size;
+    read_size = FFMIN(buf_size, mms->remaining_in_len);
+    memcpy(buf, mms->read_in_ptr, read_size);
+    mms->remaining_in_len -= read_size;
+    mms->read_in_ptr      += read_size;
+    return read_size;
+}
+
+/** Read at most one media packet (or a whole header). */
+static int read_mms_packet(MMSContext *mms, uint8_t *buf, int buf_size)
+{
+    int result = 0, read_header_size = 0;
+    int size_to_copy;
+
+    do {
+        if(read_header_size < mms->asf_header_size && !mms->is_playing) {
+            /* Read from ASF header buffer */
+            size_to_copy= FFMIN(buf_size,
+                                mms->asf_header_size - read_header_size);
+            memcpy(buf, mms->asf_header + read_header_size, size_to_copy);
+            read_header_size += size_to_copy;
+            result += size_to_copy;
+            dprintf(NULL, "Copied %d bytes from stored header. left: %d\n",
+                   size_to_copy, mms->asf_header_size - read_header_size);
+            if (mms->asf_header_size == read_header_size) {
+                av_freep(&mms->asf_header);
+                mms->is_playing = 1;
+            }
+        } else if(mms->remaining_in_len) {
+            /* Read remaining packet data to buffer.
+             * the result can not be zero because remaining_in_len is positive.*/
+            result = read_data(mms, buf, buf_size);
+        } else {
+            /* Read from network */
+            int err = mms_safe_send_recv(mms, NULL, SC_PKT_ASF_MEDIA);
+            if (err == 0) {
+                if(mms->remaining_in_len>mms->asf_packet_len) {
+                    dprintf(NULL, "Incoming packet"
+                            "larger than the asf packet size stated (%d>%d)\n",
+                            mms->remaining_in_len, mms->asf_packet_len);
+                    result= AVERROR_IO;
+                } else {
+                    // copy the data to the packet buffer.
+                    result = read_data(mms, buf, buf_size);
+                    if (result == 0) {
+                        dprintf(NULL, "read asf media paket size is zero!\n");
+                        break;
+                    }
+                }
+            } else {
+                dprintf(NULL, "read packet error!\n");
+                break;
+            }
+        }
+    } while(!result); // only return one packet.
+    return result;
+}
+
+static int send_close_packet(MMSContext *mms)
+{
+    start_command_packet(mms, CS_PKT_STREAM_CLOSE);
+    insert_command_prefixes(mms, 1, 1);
+
+    return send_command_packet(mms);
+}
+
+/** Close the MMSH/MMST connection */
+static int mms_close(URLContext *h)
+{
+    MMSContext *mms = (MMSContext *)h->priv_data;
+
+    if(mms->mms_hd) {
+        send_close_packet(mms);
+        url_close(mms->mms_hd);
+    }
+
+    /* free all separately allocated pointers in mms */
+    av_free(mms->asf_header);
+    av_freep(&h->priv_data);
+
+    return 0;
+}
+
+static int mms_open(URLContext *h, const char *uri, int flags)
+{
+    MMSContext *mms;
+    int port, err;
+    char tcpname[256];
+
+    h->is_streamed = 1;
+    mms = h->priv_data = av_mallocz(sizeof(MMSContext));
+    if (!h->priv_data)
+        return AVERROR(ENOMEM);
+
+    // only for MMS over TCP, so set proto = NULL
+    ff_url_split(NULL, 0, NULL, 0,
+            mms->host, sizeof(mms->host), &port, mms->path,
+            sizeof(mms->path), uri);
+
+    if(port<0)
+        port = 1755; // defaut mms protocol port
+
+    // establish tcp connection.
+    ff_url_join(tcpname, sizeof(tcpname), "tcp", NULL, mms->host, port, NULL);
+    err = url_open(&mms->mms_hd, tcpname, URL_RDWR);
+    if (err)
+        goto fail;
+
+    mms->packet_id        = 3;          // default, initial value.
+    mms->header_packet_id = 2;          // default, initial value.
+    err = mms_safe_send_recv(mms, send_startup_packet, SC_PKT_CLIENT_ACCEPTED);
+    if (err)
+        goto fail;
+    err = mms_safe_send_recv(mms, send_protocol_select, SC_PKT_PROTOCOL_ACCEPTED);
+    if (err)
+        goto fail;
+    err = mms_safe_send_recv(mms, send_media_file_request, SC_PKT_MEDIA_FILE_DETAILS);
+    if (err)
+        goto fail;
+    err = mms_safe_send_recv(mms, send_media_header_request, SC_PKT_HEADER_REQUEST_ACCEPTED);
+    if (err)
+        goto fail;
+    err = mms_safe_send_recv(mms, NULL, SC_PKT_ASF_HEADER);
+    if (err)
+        goto fail;
+    if((mms->incoming_flags != 0X08) && (mms->incoming_flags != 0X0C))
+        goto fail;
+    err = asf_header_parser(mms);
+    if (err) {
+        dprintf(NULL, "asf header parsed failed!\n");
+        goto fail;
+    }
+    mms->header_parsed = 1;
+
+    if (!mms->asf_packet_len || !mms->stream_num)
+        goto fail;
+
+    dprintf(NULL, "Leaving open (success)\n");
+    return 0;
+fail:
+    mms_close(h);
+    dprintf(NULL, "Leaving open (failure: %d)\n", err);
+    return err;
+}
+
+static int send_media_packet_request(MMSContext *mms)
+{
+    start_command_packet(mms, CS_PKT_START_FROM_PKT_ID);
+    insert_command_prefixes(mms, 1, 0x0001FFFF);
+    bytestream_put_le64(&mms->write_out_ptr, 0);          // seek timestamp
+    bytestream_put_le32(&mms->write_out_ptr, 0xffffffff); // unknown
+    bytestream_put_le32(&mms->write_out_ptr, 0xffffffff); // packet offset
+    bytestream_put_byte(&mms->write_out_ptr, 0xff);       // max stream time limit
+    bytestream_put_byte(&mms->write_out_ptr, 0xff);       // max stream time limit
+    bytestream_put_byte(&mms->write_out_ptr, 0xff);       // max stream time limit
+    bytestream_put_byte(&mms->write_out_ptr, 0x00);       // stream time limit flag
+
+    mms->packet_id++;                                     // new packet_id
+    bytestream_put_le32(&mms->write_out_ptr, mms->packet_id);
+    return send_command_packet(mms);
+}
+
+
+static void clear_stream_buffers(MMSContext *mms)
+{
+    mms->remaining_in_len = 0;
+    mms->read_in_ptr      = mms->in_buffer;
+}
+
+/** Read ASF data through the protocol. */
+static int mms_read(URLContext *h, uint8_t *buf, int size)
+{
+    /* TODO: see tcp.c:tcp_read() about a possible timeout scheme */
+    MMSContext *mms = h->priv_data;
+    int result = 0;
+
+    /* Since we read the header at open(), this shouldn't be possible */
+    assert(mms->header_parsed);
+
+    if (!mms->is_playing) {
+        dprintf(NULL, "mms_read() before play().\n");
+        clear_stream_buffers(mms);
+        result = mms_safe_send_recv(mms, send_stream_selection_request, SC_PKT_STREAM_ID_ACCEPTED);
+        if (result)
+            return result;
+        // send media packet request
+        result = mms_safe_send_recv(mms, send_media_packet_request, SC_PKT_MEDIA_PKT_FOLLOWS);
+        if (result) {
+            return result;
+        }
+    }
+    return read_mms_packet(mms, buf, size);
+}
+
+URLProtocol mmst_protocol = {
+    "mmst",
+    mms_open,
+    mms_read,
+    NULL, // write
+    NULL, // seek
+    mms_close,
+};