diff options
author | Michael Niedermayer <michaelni@gmx.at> | 2003-08-20 11:57:00 +0400 |
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committer | Michael Niedermayer <michaelni@gmx.at> | 2003-08-20 11:57:00 +0400 |
commit | 743739d2c5d271d81c971f17c49982ce7fd543a1 (patch) | |
tree | 3c35976e47facff91bcfadb20ce5bad0dd909dc7 /libavcodec/resample.c | |
parent | b928ec649c6f836858dedd3a62909a31af20430a (diff) |
AC3 encoding patch ba (Ross Martin <ffmpeg at ross dot interwrx dot com>)
Originally committed as revision 2129 to svn://svn.ffmpeg.org/ffmpeg/trunk
Diffstat (limited to 'libavcodec/resample.c')
-rw-r--r-- | libavcodec/resample.c | 43 |
1 files changed, 38 insertions, 5 deletions
diff --git a/libavcodec/resample.c b/libavcodec/resample.c index 86bed847c4..c4ae085f93 100644 --- a/libavcodec/resample.c +++ b/libavcodec/resample.c @@ -194,6 +194,23 @@ static void stereo_mux(short *output, short *input1, short *input2, int n) } } +static void ac3_5p1_mux(short *output, short *input1, short *input2, int n) +{ + int i; + short l,r; + + for(i=0;i<n;i++) { + l=*input1++; + r=*input2++; + *output++ = l; /* left */ + *output++ = (l/2)+(r/2); /* center */ + *output++ = r; /* right */ + *output++ = 0; /* left surround */ + *output++ = 0; /* right surroud */ + *output++ = 0; /* low freq */ + } +} + static int mono_resample(ReSampleChannelContext *s, short *output, short *input, int nb_samples) { short *buf1; @@ -225,12 +242,18 @@ ReSampleContext *audio_resample_init(int output_channels, int input_channels, ReSampleContext *s; int i; - if (output_channels > 2 || input_channels > 2) - return NULL; + if ( input_channels > 2) + { + printf("Resampling with input channels greater than 2 unsupported."); + return NULL; + } s = av_mallocz(sizeof(ReSampleContext)); if (!s) - return NULL; + { + printf("Can't allocate memory for resample context."); + return NULL; + } s->ratio = (float)output_rate / (float)input_rate; @@ -241,6 +264,14 @@ ReSampleContext *audio_resample_init(int output_channels, int input_channels, if (s->output_channels < s->filter_channels) s->filter_channels = s->output_channels; +/* + * ac3 output is the only case where filter_channels could be greater than 2. + * input channels can't be greater than 2, so resample the 2 channels and then + * expand to 6 channels after the resampling. + */ + if(s->filter_channels>2) + s->filter_channels = 2; + for(i=0;i<s->filter_channels;i++) { init_mono_resample(&s->channel_ctx[i], s->ratio); } @@ -279,10 +310,10 @@ int audio_resample(ReSampleContext *s, short *output, short *input, int nb_sampl buftmp2[0] = bufin[0]; buftmp3[0] = output; stereo_to_mono(buftmp2[0], input, nb_samples); - } else if (s->output_channels == 2 && s->input_channels == 1) { + } else if (s->output_channels >= 2 && s->input_channels == 1) { buftmp2[0] = input; buftmp3[0] = bufout[0]; - } else if (s->output_channels == 2) { + } else if (s->output_channels >= 2) { buftmp2[0] = bufin[0]; buftmp2[1] = bufin[1]; buftmp3[0] = bufout[0]; @@ -303,6 +334,8 @@ int audio_resample(ReSampleContext *s, short *output, short *input, int nb_sampl mono_to_stereo(output, buftmp3[0], nb_samples1); } else if (s->output_channels == 2) { stereo_mux(output, buftmp3[0], buftmp3[1], nb_samples1); + } else if (s->output_channels == 6) { + ac3_5p1_mux(output, buftmp3[0], buftmp3[1], nb_samples1); } av_free(bufin[0]); |