]> git.sesse.net Git - vlc/blobdiff - modules/packetizer/mpeg4video.c
* h264: bug fix (give valid date + split at the right place).
[vlc] / modules / packetizer / mpeg4video.c
index 8f2055defa81b2d65bdb8cf7f7eb892a5d57bf09..2801b0e93e88f0a585517a4c1e02b1356995c69c 100644 (file)
@@ -1,11 +1,12 @@
 /*****************************************************************************
- * mpeg4video.c:
+ * mpeg4video.c: mpeg 4 video packetizer
  *****************************************************************************
  * Copyright (C) 2001, 2002 VideoLAN
- * $Id: mpeg4video.c,v 1.1 2002/12/14 21:32:41 fenrir Exp $
+ * $Id$
  *
  * Authors: Laurent Aimar <fenrir@via.ecp.fr>
  *          Eric Petit <titer@videolan.org>
+ *          Gildas Bazin <gbazin@videolan.org>
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
 /*****************************************************************************
  * Preamble
  *****************************************************************************/
+#include <stdlib.h>                                      /* malloc(), free() */
+
 #include <vlc/vlc.h>
-#include <vlc/aout.h>
 #include <vlc/decoder.h>
-#include <vlc/input.h>
 #include <vlc/sout.h>
 
-#include <stdlib.h>                                      /* malloc(), free() */
-#include <string.h>                                              /* strdup() */
-
-/*****************************************************************************
- * Local prototypes
- *****************************************************************************/
-typedef struct packetizer_thread_s
-{
-    /* Input properties */
-    decoder_fifo_t          *p_fifo;
-    bit_stream_t            bit_stream;
-
-    mtime_t                 i_dts;
-
-    /* Output properties */
-    sout_input_t            *p_sout_input;
-    sout_packet_format_t    output_format;
-
-
-    sout_buffer_t           *p_vol;
-    int                     i_vop_since_vol;
-} packetizer_thread_t;
-
-static int  Open    ( vlc_object_t * );
-static int  Run     ( decoder_fifo_t * );
-
-static int  InitThread     ( packetizer_thread_t * );
-static void PacketizeThread   ( packetizer_thread_t * );
-static void EndThread      ( packetizer_thread_t * );
+#include "vlc_bits.h"
 
 /*****************************************************************************
  * Module descriptor
  *****************************************************************************/
+static int  Open ( vlc_object_t * );
+static void Close( vlc_object_t * );
 
 vlc_module_begin();
-    set_description( _("MPEG-4 packetizer") );
+    set_category( CAT_SOUT );
+    set_subcategory( SUBCAT_SOUT_PACKETIZER );
+    set_description( _("MPEG4 video packetizer") );
     set_capability( "packetizer", 50 );
-    set_callbacks( Open, NULL );
+    set_callbacks( Open, Close );
 vlc_module_end();
 
+
+/****************************************************************************
+ * Local prototypes
+ ****************************************************************************/
+static block_t *Packetize( decoder_t *, block_t ** );
+
+struct decoder_sys_t
+{
+    /*
+     * Common properties
+     */
+    mtime_t i_interpolated_pts;
+    mtime_t i_interpolated_dts;
+    mtime_t i_last_ref_pts;
+    mtime_t i_last_time_ref;
+    mtime_t i_time_ref;
+    mtime_t i_last_time;
+    mtime_t i_last_timeincr;
+
+    vlc_bool_t  b_vop;
+    int         i_buffer;
+    int         i_buffer_size;
+    uint8_t     *p_buffer;
+    unsigned int i_flags;
+
+    int         i_fps_num;
+    int         i_fps_den;
+    int         i_last_incr;
+    int         i_last_incr_diff;
+
+    vlc_bool_t  b_frame;
+};
+
+static int m4v_FindStartCode( uint8_t **, uint8_t * );
+static int m4v_VOLParse( decoder_t *, es_format_t *, uint8_t *, int );
+static int vlc_log2( unsigned int );
+
 #define VIDEO_OBJECT_MASK                       0x01f
 #define VIDEO_OBJECT_LAYER_MASK                 0x00f
 
@@ -92,19 +106,19 @@ vlc_module_end();
 #define TEXTURE_SNR_LAYER_START_CODE            0x1c0
 
 /*****************************************************************************
- * OpenDecoder: probe the packetizer and return score
- *****************************************************************************
- * Tries to launch a decoder and return score so that the interface is able
- * to choose.
+ * Open: probe the packetizer and return score
  *****************************************************************************/
 static int Open( vlc_object_t *p_this )
 {
-    decoder_fifo_t *p_fifo = (decoder_fifo_t*) p_this;
-
-    p_fifo->pf_run = Run;
+    decoder_t     *p_dec = (decoder_t*)p_this;
+    decoder_sys_t *p_sys;
 
-    switch(  p_fifo->i_fourcc )
+    switch( p_dec->fmt_in.i_codec )
     {
+        case VLC_FOURCC( 'm', '4', 's', '2'):
+        case VLC_FOURCC( 'M', '4', 'S', '2'):
+        case VLC_FOURCC( 'm', 'p', '4', 's'):
+        case VLC_FOURCC( 'M', 'P', '4', 'S'):
         case VLC_FOURCC( 'm', 'p', '4', 'v'):
         case VLC_FOURCC( 'D', 'I', 'V', 'X'):
         case VLC_FOURCC( 'd', 'i', 'v', 'x'):
@@ -112,247 +126,423 @@ static int Open( vlc_object_t *p_this )
         case VLC_FOURCC( 'X', 'v', 'i', 'D'):
         case VLC_FOURCC( 'x', 'v', 'i', 'd'):
         case VLC_FOURCC( 'D', 'X', '5', '0'):
-            return VLC_SUCCESS;
+        case VLC_FOURCC( 'd', 'x', '5', '0'):
+        case VLC_FOURCC( 0x04, 0,   0,   0):
+        case VLC_FOURCC( '3', 'I', 'V', '2'):
+        case VLC_FOURCC( 'm', '4', 'c', 'c'):
+        case VLC_FOURCC( 'M', '4', 'C', 'C'):
+            break;
+
         default:
             return VLC_EGENERIC;
     }
-}
-
-/*****************************************************************************
- * RunDecoder: this function is called just after the thread is created
- *****************************************************************************/
-static int Run( decoder_fifo_t *p_fifo )
-{
-    packetizer_thread_t *p_pack;
-    int b_error;
 
-    msg_Info( p_fifo, "Running MPEG-4 packetizer" );
-    if( !( p_pack = malloc( sizeof( packetizer_thread_t ) ) ) )
+    /* Allocate the memory needed to store the decoder's structure */
+    if( ( p_dec->p_sys = p_sys = malloc( sizeof(decoder_sys_t) ) ) == NULL )
     {
-        msg_Err( p_fifo, "out of memory" );
-        DecoderError( p_fifo );
-        return( -1 );
+        msg_Err( p_dec, "out of memory" );
+        return VLC_EGENERIC;
     }
-    memset( p_pack, 0, sizeof( packetizer_thread_t ) );
+    memset( p_sys, 0, sizeof(decoder_sys_t) );
 
-    p_pack->p_fifo = p_fifo;
+    /* Setup properties */
+    es_format_Copy( &p_dec->fmt_out, &p_dec->fmt_in );
+    p_dec->fmt_out.i_codec = VLC_FOURCC( 'm', 'p', '4', 'v' );
 
-    if( InitThread( p_pack ) != 0 )
+    if( p_dec->fmt_in.i_extra )
     {
-        DecoderError( p_fifo );
-        return( -1 );
+        /* We have a vol */
+        p_dec->fmt_out.i_extra = p_dec->fmt_in.i_extra;
+        p_dec->fmt_out.p_extra = malloc( p_dec->fmt_in.i_extra );
+        memcpy( p_dec->fmt_out.p_extra, p_dec->fmt_in.p_extra,
+                p_dec->fmt_in.i_extra );
+
+        msg_Dbg( p_dec, "opening with vol size:%d", p_dec->fmt_in.i_extra );
+        m4v_VOLParse( p_dec, &p_dec->fmt_out,
+                      p_dec->fmt_out.p_extra, p_dec->fmt_out.i_extra );
     }
-
-    while( ( !p_pack->p_fifo->b_die )&&( !p_pack->p_fifo->b_error ) )
+    else
     {
-        PacketizeThread( p_pack );
+        /* No vol, we'll have to look for one later on */
+        p_dec->fmt_out.i_extra = 0;
+        p_dec->fmt_out.p_extra = 0;
     }
 
+    /* Set callback */
+    p_dec->pf_packetize = Packetize;
 
-    if( ( b_error = p_pack->p_fifo->b_error ) )
-    {
-        DecoderError( p_pack->p_fifo );
-    }
-
-    EndThread( p_pack );
-    if( b_error )
-    {
-        return( -1 );
-    }
-
-    return( 0 );
+    return VLC_SUCCESS;
 }
 
+/*****************************************************************************
+ * Close: clean up the packetizer
+ *****************************************************************************/
+static void Close( vlc_object_t *p_this )
+{
+    decoder_t *p_dec = (decoder_t*)p_this;
 
-#define FREE( p ) if( p ) free( p ); p = NULL
+    if( p_dec->p_sys->p_buffer ) free( p_dec->p_sys->p_buffer );
+    free( p_dec->p_sys );
+}
 
-static int CopyUntilNextStartCode( packetizer_thread_t   *p_pack,
-                                   sout_buffer_t  *p_sout_buffer,
-                                   int            *pi_pos )
+/****************************************************************************
+ * Packetize: the whole thing
+ ****************************************************************************/
+static block_t *Packetize( decoder_t *p_dec, block_t **pp_block )
 {
-    int i_copy = 0;
-
-    do
-    {
-        p_sout_buffer->p_buffer[(*pi_pos)++] =
-        GetBits( &p_pack->bit_stream, 8 );
-        i_copy++;
+    decoder_sys_t *p_sys = p_dec->p_sys;
 
-        if( *pi_pos + 2048 > p_sout_buffer->i_allocated_size )
-        {
-            sout_BufferRealloc( p_pack->p_sout_input->p_sout,
-                                p_sout_buffer,
-                                p_sout_buffer->i_allocated_size + 50 * 1024);
-        }
+    block_t *p_chain_out = NULL;
+    block_t *p_block;
+    uint8_t *p_vol = NULL;
+    uint8_t *p_start;
 
-    } while( ShowBits( &p_pack->bit_stream, 24 ) != 0x01 &&
-             !p_pack->p_fifo->b_die && !p_pack->p_fifo->b_error );
+    if( !pp_block || !*pp_block ) return NULL;
 
-    return( i_copy );
-}
+    p_block = *pp_block;
 
-static int sout_BufferAddMem( sout_instance_t *p_sout,
-                              sout_buffer_t   *p_buffer,
-                              int             i_mem,
-                              uint8_t         *p_mem )
-{
-    if( p_buffer->i_size + i_mem >= p_buffer->i_allocated_size )
+    /* Append data */
+    if( p_sys->i_buffer + p_block->i_buffer > p_sys->i_buffer_size )
     {
-        sout_BufferRealloc( p_sout,
-                            p_buffer,
-                            p_buffer->i_size + i_mem + 1024 );
+        p_sys->i_buffer_size += p_block->i_buffer + 1024;
+        p_sys->p_buffer = realloc( p_sys->p_buffer, p_sys->i_buffer_size );
     }
-    memcpy( p_buffer->p_buffer + p_buffer->i_size, p_mem, i_mem );
-    p_buffer->i_size += i_mem;
+    memcpy( &p_sys->p_buffer[p_sys->i_buffer], p_block->p_buffer,
+            p_block->i_buffer );
+    p_sys->i_buffer += p_block->i_buffer;
 
-    return( i_mem );
-}
-
-/*****************************************************************************
- * InitThread: initialize data before entering main loop
- *****************************************************************************/
-
-static int InitThread( packetizer_thread_t *p_pack )
-{
-    p_pack->i_dts = 0;
-    p_pack->p_vol = NULL;
-    p_pack->i_vop_since_vol = 0;
-    p_pack->output_format.i_cat = VIDEO_ES;
-    p_pack->output_format.i_fourcc = VLC_FOURCC( 'm', 'p', '4', 'v' );
-
-    if( InitBitstream( &p_pack->bit_stream, p_pack->p_fifo,
-                       NULL, NULL ) != VLC_SUCCESS )
+    if( p_sys->i_buffer > 10*1000000 )
     {
-        msg_Err( p_pack->p_fifo, "cannot initialize bitstream" );
-        return -1;
+        msg_Err( p_dec, "mmh reseting context" );
+        p_sys->i_buffer = 0;
     }
 
-    p_pack->p_sout_input =
-        sout_InputNew( p_pack->p_fifo,
-                       &p_pack->output_format );
-
-    if( !p_pack->p_sout_input )
+    /* Search vop */
+    p_start = &p_sys->p_buffer[p_sys->i_buffer - p_block->i_buffer - 4];
+    if( p_start < p_sys->p_buffer )
     {
-        msg_Err( p_pack->p_fifo,
-                 "cannot add a new stream" );
-        return( -1 );
+        p_start = p_sys->p_buffer;
     }
+    for( ;; )
+    {
+        if( m4v_FindStartCode( &p_start, &p_sys->p_buffer[p_sys->i_buffer] ) )
+        {
+            block_Release( p_block );
+            *pp_block = NULL;
+            return p_chain_out;
+        }
+        /* fprintf( stderr, "start code=0x1%2.2x\n", p_start[3] ); */
 
-    return( 0 );
-}
+        if( p_vol )
+        {
+            /* Copy the complete VOL */
+            p_dec->fmt_out.i_extra = p_start - p_vol;
+            p_dec->fmt_out.p_extra =
+                realloc( p_dec->fmt_out.p_extra, p_dec->fmt_out.i_extra );
+            memcpy( p_dec->fmt_out.p_extra, p_vol, p_dec->fmt_out.i_extra );
+            m4v_VOLParse( p_dec, &p_dec->fmt_out,
+                          p_dec->fmt_out.p_extra, p_dec->fmt_out.i_extra );
+
+            p_vol = NULL;
+        }
+        if( p_sys->b_vop )
+        {
+            /* Output the complete VOP we have */
+            int     i_out = p_start - p_sys->p_buffer;
+            block_t *p_out = block_New( p_dec, i_out );
 
-/*****************************************************************************
- * PacketizeThread: packetize an unit (here copy a complete pes)
- *****************************************************************************/
-static void PacketizeThread( packetizer_thread_t *p_pack )
-{
-    sout_instance_t *p_sout = p_pack->p_sout_input->p_sout;
-    sout_buffer_t   *p_frame;
+            /* extract data */
+            memcpy( p_out->p_buffer, p_sys->p_buffer, i_out );
+            if( i_out < p_sys->i_buffer )
+            {
+                memmove( p_sys->p_buffer, &p_sys->p_buffer[i_out],
+                         p_sys->i_buffer - i_out );
+            }
+            p_sys->i_buffer -= i_out;
+            p_start -= i_out;
 
-    uint32_t        i_startcode;
+            p_out->i_flags = p_sys->i_flags;
+            p_out->i_pts = p_sys->i_interpolated_pts;
+            p_out->i_dts = p_sys->i_interpolated_dts;
 
-    /* Idea: Copy until a vop has been found
-     *       Once a videoobject & videoobjectlayer has been found we save it
-     */
+            /* FIXME doesn't work when there is multiple VOP in one block */
+            if( p_block->i_dts > p_sys->i_interpolated_dts )
+            {
+                p_out->i_length = p_block->i_dts - p_sys->i_interpolated_dts;
+            }
 
-    p_frame = sout_BufferNew( p_sout, 20*1024 );    // FIXME
-    p_frame->i_size = 0;
+            if( p_dec->fmt_out.i_extra > 0 )
+            {
+                block_ChainAppend( &p_chain_out, p_out );
+            }
+            else
+            {
+                msg_Warn( p_dec, "waiting for VOL" );
+                block_Release( p_out );
+            }
 
-    for( ;; )
-    {
-        while( ( ( i_startcode = ShowBits( &p_pack->bit_stream, 32 ) )&0xffffff00 ) != 0x00000100 )
-        {
-            RemoveBits( &p_pack->bit_stream, 8 );
+            p_sys->b_vop = VLC_FALSE;
         }
 
-        if( i_startcode == VISUAL_OBJECT_SEQUENCE_START_CODE )
+        if( p_start[3] >= 0x20 && p_start[3] <= 0x2f )
         {
-            msg_Dbg( p_pack->p_fifo, "<visuel_object_sequence>" );
-            RemoveBits32( &p_pack->bit_stream );
+            /* Start of the VOL */
+            p_vol = p_start;
         }
-        else if( i_startcode == VISUAL_OBJECT_SEQUENCE_END_CODE )
+        else if( p_start[3] == 0xb3 )
         {
-            msg_Dbg( p_pack->p_fifo, "</visuel_object_sequence>" );
-            RemoveBits32( &p_pack->bit_stream );
+            /* GOP header */
         }
-        else
+        else if( p_start[3] == 0xb6 )
         {
-            msg_Dbg( p_pack->p_fifo, "start code:0x%8.8x", i_startcode );
-
-            if( ( i_startcode & ~VIDEO_OBJECT_MASK ) == VIDEO_OBJECT_START_CODE )
+            /* Parse the VOP */
+            bs_t s;
+            int i_modulo_time_base = 0;
+            int i_time_increment_bits;
+            int64_t i_time_increment, i_time_ref;
+
+            /* FIXME: we don't actually check we received enough data to read
+             * the VOP time increment. */
+            bs_init( &s, &p_start[4],
+                     p_sys->i_buffer - (p_start - p_sys->p_buffer) - 4 );
+
+            switch( bs_read( &s, 2 ) )
             {
-                msg_Dbg( p_pack->p_fifo, "<video_object>" );
-                CopyUntilNextStartCode( p_pack, p_frame, &p_frame->i_size );
+                case 0:
+                    p_sys->i_flags = BLOCK_FLAG_TYPE_I;
+                    break;
+                case 1:
+                    p_sys->i_flags = BLOCK_FLAG_TYPE_P;
+                    break;
+                case 2:
+                    p_sys->i_flags = BLOCK_FLAG_TYPE_B;
+                    p_sys->b_frame = VLC_TRUE;
+                    break;
+                case 3: /* gni ? */
+                    p_sys->i_flags = BLOCK_FLAG_TYPE_PB;
+                    break;
             }
-            else if( ( i_startcode & ~VIDEO_OBJECT_LAYER_MASK ) == VIDEO_OBJECT_LAYER_START_CODE )
+
+            while( bs_read( &s, 1 ) ) i_modulo_time_base++;
+            if( !bs_read1( &s ) ) continue; /* Marker */
+
+            /* VOP time increment */
+            i_time_increment_bits = vlc_log2(p_dec->p_sys->i_fps_num - 1) + 1;
+            if( i_time_increment_bits < 1 ) i_time_increment_bits = 1;
+            i_time_increment = bs_read( &s, i_time_increment_bits );
+
+            /* Interpolate PTS/DTS */
+            if( !(p_sys->i_flags & BLOCK_FLAG_TYPE_B) )
             {
-                /* first: save it */
-                if( p_pack->p_vol == NULL )
-                {
-                    p_pack->p_vol = sout_BufferNew( p_sout, 1024 );
-                }
-                p_pack->p_vol->i_size = 0;
-                CopyUntilNextStartCode( p_pack, p_pack->p_vol, &p_pack->p_vol->i_size );
-                p_pack->i_vop_since_vol = 0;
-
-                /* then: add it to p_frame */
-                sout_BufferAddMem( p_sout, p_frame,
-                                   p_pack->p_vol->i_size,
-                                   p_pack->p_vol->p_buffer );
+                p_sys->i_last_time_ref = p_sys->i_time_ref;
+                p_sys->i_time_ref +=
+                    (i_modulo_time_base * p_dec->p_sys->i_fps_num);
+                i_time_ref = p_sys->i_time_ref;
             }
-            else if( i_startcode == GROUP_OF_VOP_START_CODE )
+            else
             {
-                msg_Dbg( p_pack->p_fifo, "<group_of_vop>" );
-                if( p_pack->p_vol && p_pack->i_vop_since_vol > 100 ) // FIXME
-                {
-                    sout_BufferAddMem( p_sout, p_frame,
-                                       p_pack->p_vol->i_size,
-                                       p_pack->p_vol->p_buffer );
-                    p_pack->i_vop_since_vol = 0;
-                }
-                CopyUntilNextStartCode( p_pack, p_frame, &p_frame->i_size );
+                i_time_ref = p_sys->i_last_time_ref +
+                    (i_modulo_time_base * p_dec->p_sys->i_fps_num);
             }
-            else if( i_startcode == VOP_START_CODE )
+
+            if( p_dec->p_sys->i_fps_num )
+            p_sys->i_interpolated_pts +=
+                ( (i_time_ref + i_time_increment -
+                   p_sys->i_last_time - p_sys->i_last_timeincr) *
+                  I64C(1000000) / p_dec->p_sys->i_fps_num );
+
+            p_sys->i_last_time = i_time_ref;
+            p_sys->i_last_timeincr = i_time_increment;
+
+            /* Correct interpolated dts when we receive a new pts/dts */
+            if( p_block->i_pts > 0 )
+                p_sys->i_interpolated_pts = p_block->i_pts;
+            if( p_block->i_dts > 0 )
+                p_sys->i_interpolated_dts = p_block->i_dts;
+
+            if( (p_sys->i_flags & BLOCK_FLAG_TYPE_B) || !p_sys->b_frame )
             {
-                msg_Dbg( p_pack->p_fifo, "<vop>" );
-                if( p_pack->p_vol && p_pack->i_vop_since_vol > 100 ) // FIXME
-                {
-                    sout_BufferAddMem( p_sout, p_frame,
-                                       p_pack->p_vol->i_size,
-                                       p_pack->p_vol->p_buffer );
-                    p_pack->i_vop_since_vol = 0;
-                }
-                CopyUntilNextStartCode( p_pack, p_frame, &p_frame->i_size );
-                p_pack->i_vop_since_vol++;
-                break;
+                /* Trivial case (DTS == PTS) */
+
+                p_sys->i_interpolated_dts = p_sys->i_interpolated_pts;
+
+                if( p_block->i_pts > 0 )
+                    p_sys->i_interpolated_dts = p_block->i_pts;
+                if( p_block->i_dts > 0 )
+                    p_sys->i_interpolated_dts = p_block->i_dts;
+
+                p_sys->i_interpolated_pts = p_sys->i_interpolated_dts;
             }
             else
             {
-                msg_Dbg( p_pack->p_fifo, "unknown start code" );
-                CopyUntilNextStartCode( p_pack, p_frame, &p_frame->i_size );
+                if( p_sys->i_last_ref_pts > 0 )
+                    p_sys->i_interpolated_dts = p_sys->i_last_ref_pts;
+
+                p_sys->i_last_ref_pts = p_sys->i_interpolated_pts;
             }
 
+            p_sys->b_vop = VLC_TRUE;
+
+            /* Don't re-use the same PTS/DTS twice */
+            p_block->i_pts = p_block->i_dts = 0;
         }
+
+        p_start += 4; /* Next */
     }
+}
 
-    p_frame->i_length = 1000000 / 25;
-    p_frame->i_bitrate= 0;
-    p_frame->i_dts = p_pack->i_dts;
-    p_frame->i_pts = p_pack->i_dts;
+/****************************************************************************
+ * m4v_FindStartCode
+ ****************************************************************************/
+static int m4v_FindStartCode( uint8_t **pp_start, uint8_t *p_end )
+{
+    uint8_t *p = *pp_start;
 
-    p_pack->i_dts += 1000000 / 25;
-    sout_InputSendBuffer( p_pack->p_sout_input, p_frame );
+    /* We wait for 4+1 bytes */
+    for( p = *pp_start; p < p_end - 5; p++ )
+    {
+        if( p[0] == 0 && p[1] == 0 && p[2] == 1 )
+        {
+            *pp_start = p;
+            return VLC_SUCCESS;
+        }
+    }
+
+    *pp_start = p_end;
+    return VLC_EGENERIC;
 }
 
 
-/*****************************************************************************
- * EndThread : packetizer thread destruction
- *****************************************************************************/
-static void EndThread ( packetizer_thread_t *p_pack)
+/* look at ffmpeg av_log2 ;) */
+static int vlc_log2( unsigned int v )
 {
-    if( p_pack->p_sout_input )
+    int n = 0;
+    static const int vlc_log2_table[16] =
     {
-        sout_InputDelete( p_pack->p_sout_input );
+        0,0,1,1,2,2,2,2, 3,3,3,3,3,3,3,3
+    };
+
+    if( v&0xffff0000 )
+    {
+        v >>= 16;
+        n += 16;
     }
+    if( v&0xff00 )
+    {
+        v >>= 8;
+        n += 8;
+    }
+    if( v&0xf0 )
+    {
+        v >>= 4;
+        n += 4;
+    }
+    n += vlc_log2_table[v];
+
+    return n;
 }
 
+/* m4v_VOLParse:
+ *  TODO:
+ *      - support aspect ratio
+ */
+static int m4v_VOLParse( decoder_t *p_dec, es_format_t *fmt,
+                         uint8_t *p_vol, int i_vol )
+{
+    bs_t s;
+    int i_vo_type;
+    int i_vo_ver_id;
+    int i_ar;
+    int i_shape;
+
+    for( ;; )
+    {
+        if( p_vol[0] == 0x00 && p_vol[1] == 0x00 &&
+            p_vol[2] == 0x01 &&
+            p_vol[3] >= 0x20 && p_vol[3] <= 0x2f )
+        {
+            break;
+        }
+        p_vol++;
+        i_vol--;
+        if( i_vol <= 4 )
+        {
+            return VLC_EGENERIC;
+        }
+    }
+
+    /* parse the vol */
+    bs_init( &s, &p_vol[4], i_vol - 4 );
+
+    bs_skip( &s, 1 );   /* random access */
+    i_vo_type = bs_read( &s, 8 );
+    if( bs_read1( &s ) )
+    {
+        i_vo_ver_id = bs_read( &s, 4 );
+        bs_skip( &s, 3 );
+    }
+    else
+    {
+        i_vo_ver_id = 1;
+    }
+    i_ar = bs_read( &s, 4 );
+    if( i_ar == 0xf )
+    {
+        int i_ar_width, i_ar_height;
+
+        i_ar_width = bs_read( &s, 8 );
+        i_ar_height= bs_read( &s, 8 );
+    }
+    if( bs_read1( &s ) )
+    {
+        int i_chroma_format;
+        int i_low_delay;
+
+        /* vol control parameter */
+        i_chroma_format = bs_read( &s, 2 );
+        i_low_delay = bs_read1( &s );
+
+        if( bs_read1( &s ) )
+        {
+            bs_skip( &s, 16 );
+            bs_skip( &s, 16 );
+            bs_skip( &s, 16 );
+            bs_skip( &s, 3 );
+            bs_skip( &s, 11 );
+            bs_skip( &s, 1 );
+            bs_skip( &s, 16 );
+        }
+    }
+    /* shape 0->RECT, 1->BIN, 2->BIN_ONLY, 3->GRAY */
+    i_shape = bs_read( &s, 2 );
+    if( i_shape == 3 && i_vo_ver_id != 1 )
+    {
+        bs_skip( &s, 4 );
+    }
+
+    if( !bs_read1( &s ) ) return VLC_EGENERIC; /* Marker */
+
+    p_dec->p_sys->i_fps_num = bs_read( &s, 16 ); /* Time increment resolution*/
+    if( !p_dec->p_sys->i_fps_num ) p_dec->p_sys->i_fps_num = 1;
+
+    if( !bs_read1( &s ) ) return VLC_EGENERIC; /* Marker */
+
+    if( bs_read1( &s ) )
+    {
+        int i_time_increment_bits =
+            vlc_log2( p_dec->p_sys->i_fps_num - 1 ) + 1;
+
+        if( i_time_increment_bits < 1 ) i_time_increment_bits = 1;
+
+        p_dec->p_sys->i_fps_den = bs_read( &s, i_time_increment_bits );
+    }
+    if( i_shape == 0 )
+    {
+        bs_skip( &s, 1 );
+        fmt->video.i_width = bs_read( &s, 13 );
+        bs_skip( &s, 1 );
+        fmt->video.i_height= bs_read( &s, 13 );
+        bs_skip( &s, 1 );
+    }
+    return VLC_SUCCESS;
+}