VLC learning plan (5)-network data stream Receiving and Processing Process Analysis

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Analysis of Network Data Stream receiving and processing: the main thread loop thread in charge of processing the network packets and demultiplexing in the input. C (src/input) File

Network Data Stream Receiving and Processing Analysis

1. Main thread loop in the input. C (src/input) File

Thread in charge of processing the network packets and demultiplexing

Runthread (input_thread_t * p_input)

{

Initthread (p_input );

.............................................................

Input_selectes (p_input, p_input-> stream. p_newly_selected_es );

.............................................................

/* Read and demultiplex some data .*/

I _count = p_input-> pf_demux (p_input );

 

}

2. In the following functions:

1. Separates access, Demux, and name strings;
2. Use the module_need function to find the acess pointer Module Based on the isolated access string;
3. Find the Demux pointer module by using the module_need function based on the separated Demux string;

Static int initthread (input_thread_t * p_input)

{

Msg_dbg (p_input, "Access '% s', Demux' % s', name '% S '",

P_input-> psz_access, p_input-> psz_demux, p_input-> psz_name );

 

/* Find and open appropriate access module */

P_input-> p_access = module_need (p_input, "access ",

P_input-> psz_access, vlc_true );

.............................................................

While (! Input_fillbuffer (p_input ))

.............................................................

/* Find and open appropriate Demux module */

P_input-> p_demux =

Module_need (p_input, "Demux ",

(P_input-> psz_demux & * p_input-> psz_demux )?

P_input-> psz_demux: "$ Demux ",

(P_input-> psz_demux & * p_input-> psz_demux )?

Vlc_true: vlc_false );

.............................................................

}

3. In the PS. C (module/Demux/MPEG) File

A. Activate the activate function through macro assignment of message ing;

B. Use the activate function to assign p_input-> pf_demux = Demux;

C. Use the module_need (p_input, "MPEG-System", null, 0) function to activate p_input-> p_demux_data-> MPEG. pf_read_ps (p_input, & p_data) function (pf_read_ps );

D. Activate it in the initthread function;

 

Static int activate (vlc_object_t * p_this)

{

/* Set the Demux function */

P_input-> pf_demux = Demux;

P_input-> p_private = (void *) & p_demux-> MPEG;

P_demux-> p_module = module_need (p_input, "MPEG-System", null, 0 );

}

4. In the system. C (module/Demux/MPEG) File

Value assignment decoding module mpeg_demux_t member functions;

Static int activate (vlc_object_t * p_this)
{
Static mpeg_demux_t mpeg_demux =
{Null, readps, parseps, demuxps, readts, demuxts };
Mpeg_demux.cur_scr_time =-1;
Memcpy (p_this-> p_private, & mpeg_demux, sizeof (mpeg_demux ));

Return vlc_success;

}

And declare the function static ssize_t readps (input_thread_t * p_input, data_packet_t ** pp_data );

5. In the PS. C (module/Demux/MPEG) File

Demux (input_thread_t * p_input)

{

I _result = p_input-> p_demux_data-> MPEG. pf_read_ps (p_input, & p_data );

P_input-> p_demux_data-> MPEG. pf_demux_ps (p_input, p_data );

}

Read and separate data;

6. In the system. C (module/Demux/MPEG) File

The following figure shows the data trend.

Readps-> peek-> input_peek (src/input/input_ext-plugins.c)-> input_fillbuffert through

I _ret = p_input-> pf_read (p_input,

(Byte_t *) p_buf + sizeof (data_buffer_t) + I _remains,

P_input-> I _bufsize );

If the pf_read function Member of the input_thread_t structure is the rtpchoose function of UDP. C (modules/access ),

Enable access (UDP module) through module_need;

Activate the network read data module rtpchoose (modules/access/udp. c)-> Read-> net_read (src/MISC/net. C );

 

7. In the input_programs.c (src/input) File

Run the decoder to decode the es stream

Int input_selectes (input_thread_t * p_input, es_descriptor_t * p_es)

{

P_es-> p_dec = input_rundecoder (p_input, p_es );

}

Input_selectes (src/input/input_programs.c)-> input_rundecoder (src/input/input_dec.c)-> decoderthread-> decoderdecode-> vout_displaypicture