[vlc-devel] commit: Added a new channel extraction helper to aout. (Laurent Aimar )
git version control
git at videolan.org
Sat May 2 21:45:04 CEST 2009
vlc | branch: master | Laurent Aimar <fenrir at videolan.org> | Sat May 2 21:18:19 2009 +0200| [29e5165b2a6099a3c83bf29759a7a60225b6d90e] | committer: Laurent Aimar
Added a new channel extraction helper to aout.
They are aout_CheckChannelExtraction/aout_ChannelExtract.
They work a bit like CheckChannelReorder and ChannelReorder but does not
have there limitations. They will mainly be used to interface the aout core
with the world (demuxer, codecs, maybe output).
> http://git.videolan.org/gitweb.cgi/vlc.git/?a=commit;h=29e5165b2a6099a3c83bf29759a7a60225b6d90e
---
include/vlc_aout.h | 28 ++++++++++++
src/audio_output/common.c | 102 +++++++++++++++++++++++++++++++++++++++++++++
src/libvlccore.sym | 2 +
3 files changed, 132 insertions(+), 0 deletions(-)
diff --git a/include/vlc_aout.h b/include/vlc_aout.h
index e721fa2..00b7e2e 100644
--- a/include/vlc_aout.h
+++ b/include/vlc_aout.h
@@ -412,6 +412,34 @@ VLC_EXPORT( aout_buffer_t *, aout_OutputNextBuffer, ( aout_instance_t *, mtime_t
VLC_EXPORT( int, aout_CheckChannelReorder, ( const uint32_t *pi_chan_order_in, const uint32_t *pi_chan_order_out, uint32_t i_channel_mask, int i_channels, int *pi_chan_table ) );
VLC_EXPORT( void, aout_ChannelReorder, ( uint8_t *, int, int, const int *, int ) );
+/**
+ * This fonction will compute the extraction parameter into pi_selection to go
+ * from i_channels with their type given by pi_order_src[] into the order
+ * describe by pi_order_dst.
+ * It will also set :
+ * - *pi_channels as the number of channels that will be extracted which is
+ * lower (in case of non understood channels type) or equal to i_channels.
+ * - the layout of the channels (*pi_layout).
+ *
+ * It will return true if channel extraction is really needed, in which case
+ * aout_ChannelExtract must be used
+ *
+ * XXX It must be used when the source may have channel type not understood
+ * by VLC. In this case the channel type pi_order_src[] must be set to 0.
+ * XXX It must also be used if multiple channels have the same type.
+ */
+VLC_EXPORT( bool, aout_CheckChannelExtraction, ( int *pi_selection, uint32_t *pi_layout, int *pi_channels, const uint32_t pi_order_dst[AOUT_CHAN_MAX], const uint32_t *pi_order_src, int i_channels ) );
+
+/**
+ * Do the actual channels extraction using the parameters created by
+ * aout_CheckChannelExtraction.
+ *
+ * XXX this function does not work in place (p_dst and p_src must not overlap).
+ * XXX Only 8, 16, 24, 32, 64 bits per sample are supported.
+ */
+VLC_EXPORT( void, aout_ChannelExtract, ( void *p_dst, int i_dst_channels, const void *p_src, int i_src_channels, int i_sample_count, const int *pi_selection, int i_bits_per_sample ) );
+
+/* */
VLC_EXPORT( unsigned int, aout_FormatNbChannels, ( const audio_sample_format_t * p_format ) LIBVLC_USED );
VLC_EXPORT( unsigned int, aout_BitsPerSample, ( vlc_fourcc_t i_format ) LIBVLC_USED );
VLC_EXPORT( void, aout_FormatPrepare, ( audio_sample_format_t * p_format ) );
diff --git a/src/audio_output/common.c b/src/audio_output/common.c
index 61ef092..806cb99 100644
--- a/src/audio_output/common.c
+++ b/src/audio_output/common.c
@@ -648,3 +648,105 @@ void aout_ChannelReorder( uint8_t *p_buf, int i_buffer,
}
}
}
+
+/*****************************************************************************
+ * aout_ChannelExtract:
+ *****************************************************************************/
+static inline void ExtractChannel( uint8_t *pi_dst, int i_dst_channels,
+ const uint8_t *pi_src, int i_src_channels,
+ int i_sample_count,
+ const int *pi_selection, int i_bytes )
+{
+ for( int i = 0; i < i_sample_count; i++ )
+ {
+ for( int j = 0; j < i_dst_channels; j++ )
+ memcpy( &pi_dst[j * i_bytes], &pi_src[pi_selection[j] * i_bytes], i_bytes );
+ pi_dst += i_dst_channels * i_bytes;
+ pi_src += i_src_channels * i_bytes;
+ }
+}
+
+void aout_ChannelExtract( void *p_dst, int i_dst_channels,
+ const void *p_src, int i_src_channels,
+ int i_sample_count, const int *pi_selection, int i_bits_per_sample )
+{
+ /* It does not work in place */
+ assert( p_dst != p_src );
+
+ /* Force the compiler to inline for the specific cases so it can optimize */
+ if( i_bits_per_sample == 8 )
+ ExtractChannel( p_dst, i_dst_channels, p_src, i_src_channels, i_sample_count, pi_selection, 1 );
+ else if( i_bits_per_sample == 16 )
+ ExtractChannel( p_dst, i_dst_channels, p_src, i_src_channels, i_sample_count, pi_selection, 2 );
+ else if( i_bits_per_sample == 24 )
+ ExtractChannel( p_dst, i_dst_channels, p_src, i_src_channels, i_sample_count, pi_selection, 3 );
+ else if( i_bits_per_sample == 32 )
+ ExtractChannel( p_dst, i_dst_channels, p_src, i_src_channels, i_sample_count, pi_selection, 4 );
+ else if( i_bits_per_sample == 64 )
+ ExtractChannel( p_dst, i_dst_channels, p_src, i_src_channels, i_sample_count, pi_selection, 8 );
+}
+
+bool aout_CheckChannelExtraction( int *pi_selection,
+ uint32_t *pi_layout, int *pi_channels,
+ const uint32_t pi_order_dst[AOUT_CHAN_MAX],
+ const uint32_t *pi_order_src, int i_channels )
+{
+ const uint32_t pi_order_dual_mono[] = { AOUT_CHAN_LEFT, AOUT_CHAN_RIGHT };
+ uint32_t i_layout = 0;
+ int i_out = 0;
+ int pi_index[AOUT_CHAN_MAX];
+
+ /* */
+ if( !pi_order_dst )
+ pi_order_dst = pi_vlc_chan_order_wg4;
+
+ /* Detect special dual mono case */
+ if( i_channels == 2 &&
+ pi_order_src[0] == AOUT_CHAN_CENTER && pi_order_src[1] == AOUT_CHAN_CENTER )
+ {
+ i_layout |= AOUT_CHAN_DUALMONO;
+ pi_order_src = pi_order_dual_mono;
+ }
+
+ /* */
+ for( int i = 0; i < i_channels; i++ )
+ {
+ /* Ignore unknown or duplicated channels or not present in output */
+ if( !pi_order_src[i] || (i_layout & pi_order_src[i]) )
+ continue;
+
+ for( int j = 0; j < AOUT_CHAN_MAX; j++ )
+ {
+ if( pi_order_dst[j] == pi_order_src[i] )
+ {
+ assert( i_out < AOUT_CHAN_MAX );
+ pi_index[i_out++] = i;
+ i_layout |= pi_order_src[i];
+ break;
+ }
+ }
+ }
+
+ /* */
+ for( int i = 0, j = 0; i < AOUT_CHAN_MAX; i++ )
+ {
+ for( int k = 0; k < i_out; k++ )
+ {
+ if( pi_order_dst[i] == pi_order_src[pi_index[k]] )
+ {
+ pi_selection[j++] = pi_index[k];
+ break;
+ }
+ }
+ }
+
+ *pi_layout = i_layout;
+ *pi_channels = i_out;
+
+ for( int i = 0; i < i_out; i++ )
+ {
+ if( pi_selection[i] != i )
+ return true;
+ }
+ return i_out == i_channels;
+}
diff --git a/src/libvlccore.sym b/src/libvlccore.sym
index f714221..91f2d79 100644
--- a/src/libvlccore.sym
+++ b/src/libvlccore.sym
@@ -6,8 +6,10 @@ __ACL_Duplicate
ACL_LoadFile
AddMD5
aout_BitsPerSample
+aout_ChannelExtract
aout_ChannelReorder
aout_ChannelsRestart
+aout_CheckChannelExtraction
aout_CheckChannelReorder
aout_DateGet
aout_DateIncrement
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