[xiph-commits] r16020 - in trunk/ffmpeg2theora: . patches

[j at svn.xiph.org]

Author: j
Date: 2009-05-20 02:37:05 -0700 (Wed, 20 May 2009)
New Revision: 16020

Added:
   trunk/ffmpeg2theora/patches/
   trunk/ffmpeg2theora/patches/6to2channel-resample.patch
Log:
add ffmpeg 5.1 patch

Added: trunk/ffmpeg2theora/patches/6to2channel-resample.patch
===================================================================
--- trunk/ffmpeg2theora/patches/6to2channel-resample.patch	                        (rev 0)
+++ trunk/ffmpeg2theora/patches/6to2channel-resample.patch	2009-05-20 09:37:05 UTC (rev 16020)
@@ -0,0 +1,92 @@
+Index: libavcodec/resample.c
+===================================================================
+--- libavcodec/resample.c	(revision 11509)
++++ libavcodec/resample.c	(working copy)
+@@ -37,6 +37,17 @@
+     int input_channels, output_channels, filter_channels;
+ };
+ 
++/*
++*/
++static short clip_short(int v) {
++    if (v < -32768)
++        v = -32768;
++    else if (v > 32767)
++        v = 32767;
++    return (short) v;
++}
++
++
+ /* n1: number of samples */
+ static void stereo_to_mono(short *output, short *input, int n1)
+ {
+@@ -88,14 +99,43 @@
+     }
+ }
+ 
+-/* XXX: should use more abstract 'N' channels system */
+-static void stereo_split(short *output1, short *output2, short *input, int n)
+-{
++/* XXX: make this better.  channels will always be >= 2.
++ - Left = front_left + rear_gain * rear_left + center_gain * center
++ - Right = front_right + rear_gain * rear_right + center_gain * center
++ where rear_gain is usually around 0.5-1.0 and center_gain is almost always 0.7 (-3 dB) if I recall correctly.  */
++static void multi_to_stereo_split(short *output1, short *output2, short *input, int n, int channels) {
+     int i;
++    short l,r;
+ 
+     for(i=0;i<n;i++) {
+-        *output1++ = *input++;
+-        *output2++ = *input++;
++        if (channels == 2) {
++            /* simple stereo to stereo. Input is: l, r */
++            l = input[0];
++            r = input[1];
++        } else if (channels == 6) {
++            /* 5.1 to stereo. l, c, r, ls, rs, sw */
++            int fl,fr,c,rl,rr,lfe;
++            fl = input[0];
++            c = input[1];
++            fr = input[2];
++            rl = input[3];
++            rr = input[4];
++            lfe = input[5];
++
++            l = clip_short(fl + (0.5 * rl) + (0.7 * c));
++            r = clip_short(fr + (0.5 * rr) + (0.7 * c));
++        } else {
++            /* channels must be 3-5, or >= 7. l, c, r, ? */
++            l = input[0];
++            r = input[2];
++        }
++
++        /* output l & r. */
++        *output1++ = l;
++        *output2++ = r;
++
++        /* increment input. */
++        input += channels;
+     }
+ }
+ 
+@@ -131,9 +171,9 @@
+ {
+     ReSampleContext *s;
+ 
+-    if ( input_channels > 2)
++	 if ((input_channels > 2) && (input_channels != 6))
+       {
+-        av_log(NULL, AV_LOG_ERROR, "Resampling with input channels greater than 2 unsupported.\n");
++		av_log(NULL, AV_LOG_ERROR, "Resampling with input channels other than 1,2, or 6 is unsupported.\n");
+         return NULL;
+       }
+ 
+@@ -205,7 +245,7 @@
+     } else if (s->output_channels >= 2) {
+         buftmp3[0] = bufout[0];
+         buftmp3[1] = bufout[1];
+-        stereo_split(buftmp2[0], buftmp2[1], input, nb_samples);
++        multi_to_stereo_split(buftmp2[0], buftmp2[1], input, nb_samples, s->input_channels);
+     } else {
+         buftmp3[0] = output;
+         memcpy(buftmp2[0], input, nb_samples*sizeof(short));