* Rajout du d�but du d�codeur ac3 ;

27 years ago · 22c1b3b106
2 changed files with 300 additions and 0 deletions
--- a/include/ac3_decoder.h
+++ b/include/ac3_decoder.h
@ -0,0 +1,49 @@
+/*****************************************************************************
+ * ac3_decoder.h : ac3 decoder thread interface
+ * (c)1999 VideoLAN
+ *****************************************************************************/
+
+#define AC3DEC_FRAME_SIZE (2*256)
+
+/*****************************************************************************
+ * ac3dec_frame_t
+ *****************************************************************************/
+typedef s16 ac3dec_frame_t[ AC3DEC_FRAME_SIZE ];
+
+/*****************************************************************************
+ * ac3dec_thread_t : ac3 decoder thread descriptor
+ *****************************************************************************/
+typedef struct ac3dec_thread_s
+{
+    /*
+     * Thread properties
+     */
+    vlc_thread_t        thread_id;                /* id for thread functions */
+    boolean_t           b_die;                                 /* `die' flag */
+    boolean_t           b_error;                             /* `error' flag */
+
+    /*
+     * Input properties
+     */
+    decoder_fifo_t      fifo;                  /* stores the PES stream data */
+    /* The bit stream structure handles the PES stream at the bit level */
+    bit_stream_t        bit_stream;
+
+    /*
+     * Decoder properties
+     */
+    unsigned int        total_bits_read;
+
+    /*
+     * Output properties
+     */
+    aout_fifo_t *       p_aout_fifo; /* stores the decompressed audio frames */
+    aout_thread_t *     p_aout;           /* needed to create the audio fifo */
+
+} ac3dec_thread_t;
+
+/*****************************************************************************
+ * Prototypes
+ *****************************************************************************/
+ac3dec_thread_t *       ac3dec_CreateThread( input_thread_t * p_input );
+void                    ac3dec_DestroyThread( ac3dec_thread_t * p_ac3dec );
--- a/src/ac3_decoder/ac3_decoder.c
+++ b/src/ac3_decoder/ac3_decoder.c
@ -0,0 +1,251 @@
+/*****************************************************************************
+ * ac3_decoder.c: ac3 decoder thread
+ * (c)1999 VideoLAN
+ *****************************************************************************/
+
+/*****************************************************************************
+ * Preamble
+ *****************************************************************************/
+#include <unistd.h>                                              /* getpid() */
+
+#include <stdio.h>                                           /* "intf_msg.h" */
+#include <stdlib.h>                                      /* malloc(), free() */
+#include <sys/soundcard.h>                               /* "audio_output.h" */
+#include <sys/uio.h>                                            /* "input.h" */
+
+#include "common.h"
+#include "config.h"
+#include "mtime.h"
+#include "vlc_thread.h"
+#include "debug.h"                                      /* "input_netlist.h" */
+
+#include "intf_msg.h"                        /* intf_DbgMsg(), intf_ErrMsg() */
+
+#include "input.h"                                           /* pes_packet_t */
+#include "input_netlist.h"                         /* input_NetlistFreePES() */
+#include "decoder_fifo.h"         /* DECODER_FIFO_(ISEMPTY|START|INCSTART)() */
+
+#include "audio_output.h"
+
+#include "ac3_decoder.h"
+
+/*****************************************************************************
+ * Local prototypes
+ *****************************************************************************/
+static int      InitThread              ( ac3dec_thread_t * p_adec );
+static void     RunThread               ( ac3dec_thread_t * p_adec );
+static void     ErrorThread             ( ac3dec_thread_t * p_adec );
+static void     EndThread               ( ac3dec_thread_t * p_adec );
+
+//static byte_t   GetByte                 ( bit_stream_t * p_bit_stream );
+//static void     NeedBits                ( bit_stream_t * p_bit_stream, int i_bits );
+//static void     DumpBits                ( bit_stream_t * p_bit_stream, int i_bits );
+//static int      FindHeader              ( adec_thread_t * p_adec );
+
+/*****************************************************************************
+ * ac3dec_CreateThread: creates an ac3 decoder thread
+ *****************************************************************************/
+ac3dec_thread_t * ac3dec_CreateThread( input_thread_t * p_input )
+{
+    ac3dec_thread_t *   p_ac3dec;
+
+    intf_DbgMsg("ac3dec debug: creating ac3 decoder thread\n");
+
+    /* Allocate the memory needed to store the thread's structure */
+    if ( (p_ac3dec = (ac3dec_thread_t *)malloc( sizeof(ac3dec_thread_t) )) == NULL )
+    {
+        intf_ErrMsg("ac3dec error: not enough memory for ac3dec_CreateThread() to create the new thread\n");
+        return( NULL );
+    }
+
+    /*
+     * Initialize the thread properties
+     */
+    p_ac3dec->b_die = 0;
+    p_ac3dec->b_error = 0;
+
+    /*
+     * Initialize the input properties
+     */
+    /* Initialize the decoder fifo's data lock and conditional variable and set
+     * its buffer as empty */
+    vlc_mutex_init( &p_ac3dec->fifo.data_lock );
+    vlc_cond_init( &p_ac3dec->fifo.data_wait );
+    p_ac3dec->fifo.i_start = 0;
+    p_ac3dec->fifo.i_end = 0;
+    /* Initialize the bit stream structure */
+    p_ac3dec->bit_stream.p_input = p_input;
+    p_ac3dec->bit_stream.p_decoder_fifo = &p_ac3dec->fifo;
+    p_ac3dec->bit_stream.fifo.buffer = 0;
+    p_ac3dec->bit_stream.fifo.i_available = 0;
+
+    /*
+     * Initialize the output properties
+     */
+    p_ac3dec->p_aout = p_input->p_aout;
+    p_ac3dec->p_aout_fifo = NULL;
+
+    /* Spawn the ac3 decoder thread */
+    if ( vlc_thread_create(&p_ac3dec->thread_id, "ac3 decoder", (vlc_thread_func_t)RunThread, (void *)p_ac3dec) )
+    {
+        intf_ErrMsg( "ac3dec error: can't spawn ac3 decoder thread\n" );
+        free( p_ac3dec );
+        return( NULL );
+    }
+
+    intf_DbgMsg( "ac3dec debug: ac3 decoder thread (%p) created\n", p_ac3dec );
+    return( p_ac3dec );
+}
+
+/*****************************************************************************
+ * ac3dec_DestroyThread: destroys an ac3 decoder thread
+ *****************************************************************************/
+void ac3dec_DestroyThread( ac3dec_thread_t * p_ac3dec )
+{
+    intf_DbgMsg( "ac3dec debug: requesting termination of ac3 decoder thread %p\n", p_ac3dec );
+
+    /* Ask thread to kill itself */
+    p_ac3dec->b_die = 1;
+    /* Make sure the decoder thread leaves the GetByte() function */
+    vlc_mutex_lock( &(p_ac3dec->fifo.data_lock) );
+    vlc_cond_signal( &(p_ac3dec->fifo.data_wait) );
+    vlc_mutex_unlock( &(p_ac3dec->fifo.data_lock) );
+
+    /* Waiting for the decoder thread to exit */
+    /* Remove this as soon as the "status" flag is implemented */
+    vlc_thread_join( p_ac3dec->thread_id );
+}
+
+/* Following functions are local */
+
+/*****************************************************************************
+ * decode_find_sync()
+ *****************************************************************************/
+static __inline__ int decode_find_sync( ac3dec_thread_t * p_ac3dec )
+{
+    while ( (!p_ac3dec->b_die) && (!p_ac3dec->b_error) )
+    {
+        NeedBits( &(p_ac3dec->bit_stream), 16 );
+        if ( (p_ac3dec->bit_stream.fifo.buffer >> (32 - 16)) == 0x0b77 )
+        {
+            DumpBits( &(p_ac3dec->bit_stream), 16 );
+            p_ac3dec->total_bits_read = 16;
+            return( 0 );
+        }
+        DumpBits( &(p_ac3dec->bit_stream), 1 );
+    }
+    return( -1 );
+}
+
+/*****************************************************************************
+ * InitThread : initialize an ac3 decoder thread
+ *****************************************************************************/
+static int InitThread( ac3dec_thread_t * p_ac3dec )
+{
+    aout_fifo_t         aout_fifo;
+
+    intf_DbgMsg( "ac3dec debug: initializing ac3 decoder thread %p\n", p_ac3dec );
+
+    /* Our first job is to initialize the bit stream structure with the
+     * beginning of the input stream */
+    vlc_mutex_lock( &p_ac3dec->fifo.data_lock );
+    while ( DECODER_FIFO_ISEMPTY(p_ac3dec->fifo) )
+    {
+        vlc_cond_wait( &p_ac3dec->fifo.data_wait, &p_ac3dec->fifo.data_lock );
+    }
+    p_ac3dec->bit_stream.p_ts = DECODER_FIFO_START( p_ac3dec->fifo )->p_first_ts;
+    p_ac3dec->bit_stream.i_byte = p_ac3dec->bit_stream.p_ts->i_payload_start;
+    vlc_mutex_unlock( &p_ac3dec->fifo.data_lock );
+
+    aout_fifo.i_type = AOUT_ADEC_STEREO_FIFO;
+    aout_fifo.b_stereo = 1;
+
+    aout_fifo.l_frame_size = AC3DEC_FRAME_SIZE;
+
+    /* Creating the audio output fifo */
+    if ( (p_ac3dec->p_aout_fifo = aout_CreateFifo(p_ac3dec->p_aout, &aout_fifo)) == NULL )
+    {
+        return( -1 );
+    }
+
+    intf_DbgMsg( "ac3dec debug: ac3 decoder thread %p initialized\n", p_ac3dec );
+    return( 0 );
+}
+
+/*****************************************************************************
+ * RunThread : ac3 decoder thread
+ *****************************************************************************/
+static void RunThread( ac3dec_thread_t * p_ac3dec )
+{
+    intf_DbgMsg( "ac3dec debug: running ac3 decoder thread (%p) (pid == %i)\n", p_ac3dec, getpid() );
+
+    /* Initializing the ac3 decoder thread */
+    if ( InitThread(p_ac3dec) )
+    {
+        p_ac3dec->b_error = 1;
+    }
+
+    /* ac3 decoder thread's main loop */
+    while ( (!p_ac3dec->b_die) && (!p_ac3dec->b_error) )
+    {
+        if ( decode_find_sync(p_ac3dec) == 0 )
+        {
+            fprintf( stderr, "ac3dec debug: decode_find_sync() == 0\n" );
+        }
+    }
+
+    /* If b_error is set, the ac3 decoder thread enters the error loop */
+    if ( p_ac3dec->b_error )
+    {
+        ErrorThread( p_ac3dec );
+    }
+
+    /* End of the ac3 decoder thread */
+    EndThread( p_ac3dec );
+}
+
+/*****************************************************************************
+ * ErrorThread : ac3 decoder's RunThread() error loop
+ *****************************************************************************/
+static void ErrorThread( ac3dec_thread_t * p_ac3dec )
+{
+    /* We take the lock, because we are going to read/write the start/end
+     * indexes of the decoder fifo */
+    vlc_mutex_lock( &p_ac3dec->fifo.data_lock );
+
+    /* Wait until a `die' order is sent */
+    while( !p_ac3dec->b_die )
+    {
+        /* Trash all received PES packets */
+        while( !DECODER_FIFO_ISEMPTY(p_ac3dec->fifo) )
+        {
+            input_NetlistFreePES( p_ac3dec->bit_stream.p_input, DECODER_FIFO_START(p_ac3dec->fifo) );
+	    DECODER_FIFO_INCSTART( p_ac3dec->fifo );
+        }
+
+        /* Waiting for the input thread to put new PES packets in the fifo */
+        vlc_cond_wait( &p_ac3dec->fifo.data_wait, &p_ac3dec->fifo.data_lock );
+    }
+
+    /* We can release the lock before leaving */
+    vlc_mutex_unlock( &p_ac3dec->fifo.data_lock );
+}
+
+/*****************************************************************************
+ * EndThread : ac3 decoder thread destruction
+ *****************************************************************************/
+static void EndThread( ac3dec_thread_t * p_ac3dec )
+{
+    intf_DbgMsg( "ac3dec debug: destroying ac3 decoder thread %p\n", p_ac3dec );
+
+    /* If the audio output fifo was created, we destroy it */
+    if ( p_ac3dec->p_aout_fifo != NULL )
+    {
+        aout_DestroyFifo( p_ac3dec->p_aout_fifo );
+    }
+
+    /* Destroy descriptor */
+    free( p_ac3dec );
+
+    intf_DbgMsg( "ac3dec debug: ac3 decoder thread %p destroyed\n", p_ac3dec );
+}