]> git.sesse.net Git - vlc/blobdiff - modules/packetizer/mpegvideo.c
* modules/packetizer/mpegvideo.c: Detect discontinuities and trash
[vlc] / modules / packetizer / mpegvideo.c
index 559b20d95651e4b5cd0625e6a89bda3e4c093959..97a1dd3a686b40161caf927b19599d10fd160cd3 100644 (file)
@@ -2,7 +2,7 @@
  * mpegvideo.c
  *****************************************************************************
  * Copyright (C) 2001, 2002 VideoLAN
- * $Id: mpegvideo.c,v 1.13 2003/04/16 00:12:36 fenrir Exp $
+ * $Id: mpegvideo.c,v 1.20 2003/11/07 16:53:54 massiot Exp $
  *
  * Authors: Laurent Aimar <fenrir@via.ecp.fr>
  *          Eric Petit <titer@videolan.org>
  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111, USA.
  *****************************************************************************/
 
+/*****************************************************************************
+ * Problem with this implementation:
+ *
+ * Although we should time-stamp each picture with a PTS, this isn't possible
+ * with the current implementation.
+ * The problem comes from the fact that for non-low-delay streams we can't
+ * calculate the PTS of pictures used as backward reference. Even the temporal
+ * reference number doesn't help here because all the pictures don't
+ * necessarily have the same duration (eg. 3:2 pulldown).
+ *
+ * However this doesn't really matter as far as the MPEG muxers are concerned
+ * because they allow having empty PTS fields. --gibalou
+ *****************************************************************************/
+
 /*****************************************************************************
  * Preamble
  *****************************************************************************/
@@ -47,15 +61,17 @@ typedef struct packetizer_s
     sout_packetizer_input_t *p_sout_input;
     sout_format_t           output_format;
 
-    mtime_t                 i_last_dts;
+    mtime_t                 i_interpolated_dts;
+    mtime_t                 i_old_duration;
     mtime_t                 i_last_ref_pts;
     double                  d_frame_rate;
     int                     i_progressive_sequence;
+    int                     i_low_delay;
     uint8_t                 p_sequence_header[150];
     int                     i_sequence_header_length;
     int                     i_last_sequence_header;
+    vlc_bool_t              b_expect_discontinuity;
 
-    int                     i_last_picture_structure;
 } packetizer_t;
 
 static int  Open    ( vlc_object_t * );
@@ -64,6 +80,7 @@ static int  Run     ( decoder_fifo_t * );
 static int  InitThread     ( packetizer_t * );
 static void PacketizeThread   ( packetizer_t * );
 static void EndThread      ( packetizer_t * );
+static void BitstreamCallback ( bit_stream_t *, vlc_bool_t );
 
 /*****************************************************************************
  * Module descriptor
@@ -83,16 +100,16 @@ vlc_module_end();
  *****************************************************************************/
 static int Open( vlc_object_t *p_this )
 {
-    decoder_fifo_t *p_fifo = (decoder_fifo_t*) p_this;
+    decoder_t *p_dec = (decoder_t*)p_this;
 
-    if( p_fifo->i_fourcc != VLC_FOURCC( 'm', 'p', 'g', 'v') &&
-        p_fifo->i_fourcc != VLC_FOURCC( 'm', 'p', 'g', '1') &&
-        p_fifo->i_fourcc != VLC_FOURCC( 'm', 'p', 'g', '2') )
+    if( p_dec->p_fifo->i_fourcc != VLC_FOURCC( 'm', 'p', 'g', 'v') &&
+        p_dec->p_fifo->i_fourcc != VLC_FOURCC( 'm', 'p', 'g', '1') &&
+        p_dec->p_fifo->i_fourcc != VLC_FOURCC( 'm', 'p', 'g', '2') )
     {
         return VLC_EGENERIC;
     }
 
-    p_fifo->pf_run = Run;
+    p_dec->pf_run = Run;
     return VLC_SUCCESS;
 }
 
@@ -163,16 +180,16 @@ static int InitThread( packetizer_t *p_pack )
     p_pack->output_format.i_extra_data = 0;
     p_pack->output_format.p_extra_data = NULL;
 
+    p_pack->b_expect_discontinuity = 0;
     p_pack->p_sout_input = NULL;
 
     if( InitBitstream( &p_pack->bit_stream, p_pack->p_fifo,
-                       NULL, NULL ) != VLC_SUCCESS )
+                       BitstreamCallback, (void *)p_pack ) != VLC_SUCCESS )
     {
         msg_Err( p_pack->p_fifo, "cannot initialize bitstream" );
         return -1;
     }
 
-    p_pack->i_last_picture_structure = 0x03; /* frame picture */
     return( 0 );
 }
 
@@ -180,7 +197,7 @@ static int InitThread( packetizer_t *p_pack )
 /* converting frame_rate_code to frame_rate */
 static const double pd_frame_rates[16] =
 {
-    0, 24000/1001, 24, 25, 30000/1001, 30, 50, 60000/1001, 60,
+    0, 24000.0/1001, 24, 25, 30000.0/1001, 30, 50, 60000.0/1001, 60,
     0, 0, 0, 0, 0, 0, 0
 };
 
@@ -220,14 +237,16 @@ static void PacketizeThread( packetizer_t *p_pack )
     int           i_skipped;
     mtime_t       i_duration; /* of the parsed picture */
 
-    mtime_t       i_pts;
-    mtime_t       i_dts;
+    mtime_t       i_pts = 0;
+    mtime_t       i_dts = 0;
 
     /* needed to calculate pts/dts */
     int i_temporal_ref = 0;
+    int i_picture_coding_type = 0;
     int i_picture_structure = 0x03; /* frame picture */
     int i_top_field_first = 0;
     int i_repeat_first_field = 0;
+    int i_progressive_frame = 0;
 
     if( !p_pack->p_sout_input )
     {
@@ -290,12 +309,13 @@ static void PacketizeThread( packetizer_t *p_pack )
         {
             msg_Dbg( p_pack->p_fifo, "ARRGG no extension_start_code" );
             p_pack->i_progressive_sequence = 1;
+            p_pack->i_low_delay = 1;
         }
         else
         {
             GetChunk( &p_pack->bit_stream, p_temp + i_pos, 10 );
             p_pack->i_progressive_sequence = ( p_temp[i_pos+5]&0x08 ) ? 1 : 0;
-
+            p_pack->i_low_delay = ( p_temp[i_pos+9]&0x80 ) ? 1 : 0;
             i_pos += 10;
         }
 
@@ -331,7 +351,7 @@ static void PacketizeThread( packetizer_t *p_pack )
     else
     {
         p_sout_buffer =
-                sout_BufferNew( p_pack->p_sout_input->p_sout, 100 * 1024 );
+            sout_BufferNew( p_pack->p_sout_input->p_sout, 100 * 1024 );
         i_pos = 0;
     }
 
@@ -364,11 +384,7 @@ static void PacketizeThread( packetizer_t *p_pack )
                i_pos += p_pack->i_sequence_header_length;
                p_pack->i_last_sequence_header = 0;
             }
-#if 1
-            p_pack->i_last_ref_pts =
-                   p_pack->i_last_dts +
-                        (mtime_t)( 1000000 / p_pack->d_frame_rate); /* FIXME */
-#endif
+            p_sout_buffer->i_flags |= SOUT_BUFFER_FLAGS_GOP;
             CopyUntilNextStartCode( p_pack, p_sout_buffer, &i_pos );
         }
         else if( i_code == 0x100 ) /* Picture */
@@ -379,6 +395,7 @@ static void PacketizeThread( packetizer_t *p_pack )
 
             NextPTS( &p_pack->bit_stream, &i_pts, &i_dts );
             i_temporal_ref = ShowBits( &p_pack->bit_stream, 10 );
+            i_picture_coding_type = ShowBits( &p_pack->bit_stream, 13 ) & 0x3;
 
             CopyUntilNextStartCode( p_pack, p_sout_buffer, &i_pos );
         }
@@ -403,6 +420,12 @@ static void PacketizeThread( packetizer_t *p_pack )
                     ShowBits( &p_pack->bit_stream, 25 ) & 0x01;
                 i_repeat_first_field =
                     ShowBits( &p_pack->bit_stream, 31 ) & 0x01;
+
+                GetChunk( &p_pack->bit_stream,
+                          p_sout_buffer->p_buffer + i_pos, 4 ); i_pos += 4;
+
+                i_progressive_frame =
+                    ShowBits( &p_pack->bit_stream, 1 ) & 0x01;
             }
             CopyUntilNextStartCode( p_pack, p_sout_buffer, &i_pos );
         }
@@ -421,11 +444,18 @@ static void PacketizeThread( packetizer_t *p_pack )
         }
     }
 
+    if( i_pts <= 0 && i_dts <= 0 && p_pack->i_interpolated_dts <= 0 )
+    {
+        msg_Dbg( p_pack->p_fifo, "need a starting pts/dts" );
+        sout_BufferDelete( p_pack->p_sout_input->p_sout, p_sout_buffer );
+        return;
+    }
+
     sout_BufferRealloc( p_pack->p_sout_input->p_sout,
                         p_sout_buffer, i_pos );
     p_sout_buffer->i_size = i_pos;
 
-    /* calculate dts/pts */
+    /* calculate frame duration */
     if( p_pack->i_progressive_sequence || i_picture_structure == 0x03)
     {
         i_duration = (mtime_t)( 1000000 / p_pack->d_frame_rate );
@@ -435,70 +465,83 @@ static void PacketizeThread( packetizer_t *p_pack )
         i_duration = (mtime_t)( 1000000 / p_pack->d_frame_rate / 2);
     }
 
-    /* fix i_last_dts and i_last_ref_pts with i_dts and i_pts from stream */
-    if( i_dts <= 0 && p_pack->i_last_dts <= 0 )
+    if( p_pack->i_progressive_sequence )
     {
-        msg_Dbg( p_pack->p_fifo, "need a starting pts" );
-        sout_BufferDelete( p_pack->p_sout_input->p_sout,
-                           p_sout_buffer );
-        return;
+        if( i_top_field_first == 0 && i_repeat_first_field == 1 )
+        {
+            i_duration = 2 * i_duration;
+        }
+        else if( i_top_field_first == 1 && i_repeat_first_field == 1 )
+        {
+            i_duration = 3 * i_duration;
+        }
     }
-
-#if 1
-    if( i_dts > 0 )
+    else
     {
-        //if( i_dts - p_pack->i_last_dts > 200000 ||
-        //    i_dts - p_pack->i_last_dts < 200000 )
+        if( i_picture_structure == 0x03 )
         {
-            p_pack->i_last_dts = i_dts;
-            if( i_pts > 0 )
+            if( i_progressive_frame && i_repeat_first_field )
             {
-                p_pack->i_last_ref_pts = i_pts -
-                    i_temporal_ref * (mtime_t)( 1000000 / p_pack->d_frame_rate );
+                i_duration += i_duration / 2;
             }
         }
     }
-#endif
 
-    p_sout_buffer->i_dts = p_pack->i_last_dts;
-    p_sout_buffer->i_pts = p_pack->i_last_ref_pts + 
-        i_temporal_ref * (mtime_t)( 1000000 / p_pack->d_frame_rate );
-    p_sout_buffer->i_length = i_duration;
+    if( p_pack->i_low_delay || i_picture_coding_type == 0x03 )
+    {
+        /* Trivial case (DTS == PTS) */
+        /* Correct interpolated dts when we receive a new pts/dts */
+        if( i_pts > 0 ) p_pack->i_interpolated_dts = i_pts;
+        if( i_dts > 0 ) p_pack->i_interpolated_dts = i_dts;
+    }
+    else
+    {
+        /* Correct interpolated dts when we receive a new pts/dts */
+        if( p_pack->i_last_ref_pts )
+            p_pack->i_interpolated_dts = p_pack->i_last_ref_pts;
+        if( i_dts > 0 ) p_pack->i_interpolated_dts = i_dts;
+
+        p_pack->i_last_ref_pts = i_pts;
+    }
+
+    /* Don't even try to calculate the PTS unless it is given in the
+     * original stream */
+    p_sout_buffer->i_pts = i_pts ? i_pts : -1;
+
+    p_sout_buffer->i_dts = p_pack->i_interpolated_dts;
+
+    if( p_pack->i_low_delay || i_picture_coding_type == 0x03 )
+    {
+        /* Trivial case (DTS == PTS) */
+        p_pack->i_interpolated_dts += i_duration;
+    }
+    else
+    {
+        p_pack->i_interpolated_dts += p_pack->i_old_duration;
+        p_pack->i_old_duration = i_duration;
+    }
+
+    p_sout_buffer->i_length = p_pack->i_interpolated_dts -
+                                p_sout_buffer->i_dts;
+
     p_sout_buffer->i_bitrate = (int)( 8 * i_pos * p_pack->d_frame_rate );
-    sout_InputSendBuffer( p_pack->p_sout_input, p_sout_buffer );
 
-    if( p_pack->i_progressive_sequence )
+#if 0
+    msg_Dbg( p_pack->p_fifo, "------------> dts=%lld pts=%lld duration=%lld",
+             p_sout_buffer->i_dts, p_sout_buffer->i_pts,
+             p_sout_buffer->i_length );
+#endif
+
+    if ( p_pack->b_expect_discontinuity )
     {
-        if( i_top_field_first == 0 && i_repeat_first_field == 0 )
-        {
-            p_pack->i_last_dts += i_duration;
-        }
-        else if( i_top_field_first == 0 && i_repeat_first_field == 1 )
-        {
-            p_pack->i_last_dts += 2 * i_duration;
-        }
-        else if( i_top_field_first == 1 && i_repeat_first_field == 1 )
-        {
-            p_pack->i_last_dts += 3 * i_duration;
-        }
+        msg_Warn( p_pack->p_fifo, "discontinuity encountered, dropping a frame" );
+        p_pack->b_expect_discontinuity = 0;
+        sout_BufferDelete( p_pack->p_sout_input->p_sout, p_sout_buffer );
     }
     else
     {
-        if( i_picture_structure == 0x03 )
-        {
-            p_pack->i_last_dts += i_duration;
-        }
-        else if( i_picture_structure == p_pack->i_last_picture_structure )
-        {
-            p_pack->i_last_dts += 2 * i_duration;
-        }
-        else if( ( !i_top_field_first && i_picture_structure == 0x01 ) ||
-                 (  i_top_field_first && i_picture_structure == 0x02 ) )
-        {
-            p_pack->i_last_dts += 2 * i_duration;
-        }
+        sout_InputSendBuffer( p_pack->p_sout_input, p_sout_buffer );
     }
-    p_pack->i_last_picture_structure = i_picture_structure;
 }
 
 
@@ -512,3 +555,21 @@ static void EndThread ( packetizer_t *p_pack)
         sout_InputDelete( p_pack->p_sout_input );
     }
 }
+
+/*****************************************************************************
+ * BitstreamCallback: Import parameters from the new data/PES packet
+ *****************************************************************************
+ * This function is called by input's NextDataPacket.
+ *****************************************************************************/
+static void BitstreamCallback ( bit_stream_t * p_bit_stream,
+                                vlc_bool_t b_new_pes )
+{
+    packetizer_t * p_pack = (packetizer_t *)p_bit_stream->p_callback_arg;
+
+    if( p_bit_stream->p_data->b_discard_payload
+            || (b_new_pes && p_bit_stream->p_pes->b_discontinuity) )
+    {
+        p_pack->b_expect_discontinuity = 1;
+    }
+}
+