Hi
On Tue, Jan 02, 2007 at 04:51:07PM -0600, Ryan Martell wrote:
> Hi--
>
> Attached is a native mms implementation. I did this from the ground
> up working off the specification, with the exception of borrowing the
> packet output debug routine from libmms, which I will probably remove
> before final submission. (I was using the libmms debug output stuff
> against my stuff to find my bugs)
>
> This is a rough draft only; I'm sort of interested in what people
> think about this method of implementation.
>
> Things I know about:
> 1) fprintfs must go
> 2) there may be trailing whitespace, etc.
>
> Key questions:
> 1) is the interface to asf.[ch] satisfactory?
iam not entirely happy with it but i expected the initial version to look
worse
> 2) Using a URLProtocol instead was an option, but it doesn't support
> streaming by timestamp. So instead I mirrored rtp stuff.
iam fine with a mms AVInputFormat but the way the mms and asf demuxers
are connected together is somewhat ugly
> 3) How can I get the local ip and port from a url_XXX tcp
> connection? It doesn't seem currently available in. Is this correct?
> 4) MMS has parameters for the tcp connection bitrate; and if there
> are multiple encodings in the file, it will choose the best ones. I
> am currently only streaming the first audio and first video stream.
> How would i get the bandwidth input from the user? I know we don't
> want to add new AVOptions that aren't globally useful. Also, I could
> ask for audio only in this manor.
see AVStream.discard
[...]
> @@ -567,7 +571,9 @@
> if (asf->packet_size_left < FRAME_HEADER_SIZE
> || asf->packet_segments < 1) {
> //asf->packet_size_left <= asf->packet_padsize) {
> - int ret = asf->packet_size_left + asf->packet_padsize;
> + int ret;
> + if(!load_packet) {
> + ret = asf->packet_size_left + asf->packet_padsize;
> //printf("PacketLeftSize:%d Pad:%d Pos:%"PRId64"\n", asf->packet_size_left, asf->packet_padsize, url_ftell(pb));
> if((url_ftell(&s->pb) + ret - s->data_offset) % asf->packet_size)
> ret += asf->packet_size - ((url_ftell(&s->pb) + ret - s->data_offset) % asf->packet_size);
> @@ -578,10 +584,18 @@
> if (asf->data_object_size != (uint64_t)-1 &&
> (asf->packet_pos - asf->data_object_offset >= asf->data_object_size))
> return AVERROR_IO; /* Do not exceed the size of the data object */
> - ret = asf_get_packet(s);
> + ret = asf_get_packet(s, asf, pb);
> //printf("READ ASF PACKET %d r:%d c:%d\n", ret, asf->packet_size_left, pc++);
> if (ret < 0 || url_feof(pb))
> return AVERROR_IO;
> + } else {
> + asf->packet_pos= asf->data_object_offset + asf->packet_seq * asf->packet_size;
> + assert(load_packet);
> + ret= load_packet(opaque, pb);
> + if(ret<0 || url_feof(pb)) return AVERROR_IO;
> + ret = asf_get_packet(s, asf, pb);
> + if (ret < 0 || url_feof(pb)) return AVERROR_IO;
> + }
the last 2 lines are common in both cases and can be put outside of the
if/else
[...]
> enum {
> DEFAULT_MMS_PORT= 1755,
>
> // client to server
> CS_PACKET_INITIAL_TYPE= 0x01,
> CS_PACKET_TIMING_DATA_REQUEST_TYPE= 0x18,
> CS_PACKET_PROTOCOL_SELECT_TYPE= 0x02,
> CS_PACKET_MEDIA_FILE_REQUEST_TYPE= 0x05,
> CS_PACKET_USER_PASSWORD_TYPE= 0x1a,
> CS_PACKET_MEDIA_HEADER_REQUEST_TYPE= 0x15,
> CS_PACKET_STREAM_ID_REQUEST_TYPE= 0x33,
> CS_PACKET_START_FROM_PACKET_ID_TYPE= 0x07,
> CS_PACKET_STREAM_PAUSE_TYPE= 0x09, // tcp left open, but data stopped.
> CS_PACKET_STREAM_CLOSE_TYPE= 0x0d,
> CS_PACKET_KEEPALIVE_TYPE= 0x1b,
>
> // server to client
> SC_PACKET_CLIENT_ACCEPTED= 0x01,
> SC_PACKET_TIMING_TEST_REPLY_TYPE= 0x15,
> SC_PACKET_PROTOCOL_ACCEPTED_TYPE= 0x02,
> SC_PACKET_PROTOCOL_FAILED_TYPE= 0x03,
> SC_PACKET_PASSWORD_REQUIRED_TYPE= 0x1a,
> SC_PACKET_MEDIA_FILE_DETAILS_TYPE= 0x06,
> SC_PACKET_HEADER_REQUEST_ACCEPTED_TYPE= 0x11,
> SC_PACKET_STREAM_ID_ACCEPTED_TYPE= 0x21,
> SC_PACKET_MEDIA_PACKET_FOLLOWS_TYPE= 0x05,
> SC_PACKET_STREAM_STOPPED_TYPE= 0x1e,
> SC_PACKET_KEEPALIVE_TYPE= 0x1b,
>
> // my psudeo packet types
> SC_PACKET_ASF_HEADER_TYPE= 0x81,
> SC_PACKET_ASF_MEDIA_TYPE= 0x82,
>
> // state machine states....
> AWAITING_SC_PACKET_CLIENT_ACCEPTED= 0,
> AWAITING_SC_PACKET_TIMING_TEST_REPLY_TYPE,
> AWAITING_CS_PACKET_PROTOCOL_ACCEPTANCE,
> AWAITING_PASSWORD_QUERY_OR_MEDIA_FILE,
> AWAITING_PACKET_HEADER_REQUEST_ACCEPTED_TYPE,
> AWAITING_STREAM_ID_ACCEPTANCE,
> AWAITING_STREAM_START_PACKET,
> AWAITING_ASF_HEADER,
> AWAITING_PAUSE_ACKNOWLEDGE,
> STREAMING,
> STREAM_DONE,
> STATE_ERROR,
> STREAM_PAUSED,
> USER_CANCELLED,
>
> MAXIMUM_PACKET_LENGTH= 512,
> KILO= 1024
not all things above have the same "type" as such they dont belong into the
same enum
[...]
> static int convert_to_unicode(char *dest, int max_length, const char *src)
> {
> char *dst= dest;
>
> while(*src && dst-dest<max_length-2) {
> *dst++= *src++;
> *dst++= 0;
> }
> *dst++= 0;
> *dst++= 0;
>
> return dst-dest;
> }
all strings in ffmpeg are supposed to be utf-8 so the name convert_to_unicode
is wrong, it rather should be something like convert_utf8_to_utf16 and should
use GET_UTF8() (unless you know that the input will be ASCII)
>
> static void generate_guid(char *dst)
> {
> char digit[]= "0123456789ABCDEF";
> int ii;
>
> // srandom(time(NULL));
> for(ii= 0; ii<36; ii++)
> {
> switch(ii)
> {
> case 8:
> case 13:
> case 18:
> case 23:
> *dst++= '-';
> break;
>
> default:
> *dst++= digit[random()%(sizeof(digit)/sizeof(digit[0]))];
random() must not be used in libraries as it changes the user applications
state, think of:
thread1:
srandom(123);
A=random();
thread2:
mms_demux();
also sizeof(char) == 1
[...]
> static int get_server_response(MMSState *mms)
> {
> // read the 8 byte header...
> int read_result;
> int packet_type= -1;
> int done;
>
> do {
> done= 1; // assume we're going to get a valid packet.
> if((read_result= read_bytes(mms, mms->incoming_buffer, 8))==8)
> {
> // check if we are a command packet...
> if(LE_32(mms->incoming_buffer + 4)==0xb00bface) {
this is ugly
(url_fdopen(xyz, mms->mms_hd);)
get_le32(xyz)
get_le32(xyz)
or similar is much cleaner
> mms->incoming_flags= mms->incoming_buffer[3];
> if((read_result= read_bytes(mms, mms->incoming_buffer+8, 4)) == 4) {
> int length_remaining= LE_32(mms->incoming_buffer+8) + 4;
>
> // read the rest of the packet....
> read_result = read_bytes(mms, mms->incoming_buffer + 12, length_remaining) ;
incoming_buffer is 4kb, length_remaining can be arbitrary, this is a
security hole
[...]
> } else {
> int length_remaining= (LE_16(mms->incoming_buffer + 6) - 8) & 0xffff;
> uint8_t *dst= mms->incoming_buffer;
> int packet_id_type;
>
> // note we cache the first 8 bytes, then fill up the buffer with the others
> mms->incoming_packet_seq = LE_32(mms->incoming_buffer);
> packet_id_type = mms->incoming_buffer[4]; // NOTE: THIS IS THE ONE I CAN CHANGE
> mms->incoming_flags = mms->incoming_buffer[5];
> mms->incoming_buffer_length = length_remaining;
>
> assert(mms->incoming_buffer_length<sizeof(mms->incoming_buffer));
assert() is not appropriate to check the validity of the input
a library must not kill the application if the input data is invalid, as
example think of your 5 open firefox browser windows closing instantly
after a single server returned an invaid http awnser
[...]
> static int mms_stream_play_from_timestamp(MMSState *mms, int64_t timestamp)
> {
> double ts= timestamp/1000;
>
> fprintf(stderr, "mms_stream_play: %lld TS: %lf\n", timestamp, ts);
> if(mms->state==STREAM_PAUSED)
> {
> timestamp= *((int64_t *)&ts);
completely non portable, see libavutil/intfloat_readwrite.*
[...]
> if((mms->incoming_flags == 0X08) || (mms->incoming_flags == 0X0C))
> {
> // we are done with the header stuff.
> ByteIOContext byte_context;
>
> fprintf(stderr, "Got the full header! (%d bytes)\n", mms->asf_header_length);
> // parse the header....
> init_put_byte(&byte_context, mms->asf_header, mms->asf_header_length, 0, NULL, NULL, NULL, NULL);
> if(ff_asf_read_header(mms->av_format_ctx, &mms->asf_context, &byte_context)==0)
> {
> int stream_count= 2;
> int ii;
>
> // send the streams we want back...
> put_flush_packet(&mms->packet_data);
> put_le32(&mms->packet_data, stream_count);
> for(ii= 0; ii<stream_count; ii++)
> {
> put_le16(&mms->packet_data, 0xffff); // flags
> put_le16(&mms->packet_data, ii+1); // stream id
> /*
> 00 = stream at full frame rate;
> 01 = only stream key frames;
> 02 = no stream, switch it off.
> */
> put_le16(&mms->packet_data, 00); // stream at full frame rate
AVStream.discard could be used here maybe?
[...]
> static int mms_read_packet(AVFormatContext *s,
> AVPacket *pkt)
> {
> MMSState *mms = s->priv_data;
> int result= 0;
>
> // fprintf(stderr, "mms_read_packet!\n");
>
> if(mms->state==STREAMING || mms->state==STREAM_PAUSED || mms->state==AWAITING_STREAM_START_PACKET)
> {
> // result= ff_asf_read_packet(s, pkt, &mms->asf_context, &mms->current_media_packet_context, load_packet, mms);
> // result= ff_asf_read_packet(s, pkt, &mms->asf_context, &mms->av_format_ctx->pb, load_packet, mms);
> result= ff_asf_read_packet_with_load_proc(s, pkt, load_packet, mms);
isnt it possible that the mms AVInputFormat provides the asf AVInputFormat
with a valid asf stream instead of this callback to get the next packet?
basically i think the mms and asf demuxers are too entangled ...
[...]
--
Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB
No human being will ever know the Truth, for even if they happen to say it
by chance, they would not even known they had done so. -- Xenophanes
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