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Split input sample deinterleaving into a separate function.

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Originally committed as revision 25989 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Justin Ruggles 2010-12-14 14:52:56 +00:00
parent 152cc52803
commit 4acc790f3c
1 changed files with 35 additions and 21 deletions
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56
libavcodec/ac3enc.c
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@ -105,6 +105,40 @@ static int16_t xcos1[128];
static int16_t xsin1[128];
/**
* Deinterleave input samples.
* Channels are reordered from FFmpeg's default order to AC-3 order.
*/
static void deinterleave_input_samples(AC3EncodeContext *s,
const int16_t *samples,
int16_t planar_samples[AC3_MAX_CHANNELS][AC3_BLOCK_SIZE+AC3_FRAME_SIZE])
{
int ch, i;
/* deinterleave and remap input samples */
for (ch = 0; ch < s->channels; ch++) {
const int16_t *sptr;
int sinc;
/* copy last 256 samples of previous frame to the start of the current frame */
memcpy(&planar_samples[ch][0], s->last_samples[ch],
AC3_BLOCK_SIZE * sizeof(planar_samples[0][0]));
/* deinterleave */
sinc = s->channels;
sptr = samples + s->channel_map[ch];
for (i = AC3_BLOCK_SIZE; i < AC3_FRAME_SIZE+AC3_BLOCK_SIZE; i++) {
planar_samples[ch][i] = *sptr;
sptr += sinc;
}
/* save last 256 samples for next frame */
memcpy(s->last_samples[ch], &planar_samples[ch][6* AC3_BLOCK_SIZE],
AC3_BLOCK_SIZE * sizeof(planar_samples[0][0]));
}
}
/**
* Initialize FFT tables.
* @param ln log2(FFT size)
@ -1092,27 +1126,7 @@ static int ac3_encode_frame(AVCodecContext *avctx,
int8_t exp_shift[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS];
int frame_bits;
/* deinterleave and remap input samples */
for (ch = 0; ch < s->channels; ch++) {
const int16_t *sptr;
int sinc;
/* copy last 256 samples of previous frame to the start of the current frame */
memcpy(&planar_samples[ch][0], s->last_samples[ch],
AC3_BLOCK_SIZE * sizeof(planar_samples[0][0]));
/* deinterleave */
sinc = s->channels;
sptr = samples + s->channel_map[ch];
for (i = AC3_BLOCK_SIZE; i < AC3_FRAME_SIZE+AC3_BLOCK_SIZE; i++) {
planar_samples[ch][i] = *sptr;
sptr += sinc;
}
/* save last 256 samples for next frame */
memcpy(s->last_samples[ch], &planar_samples[ch][6* AC3_BLOCK_SIZE],
AC3_BLOCK_SIZE * sizeof(planar_samples[0][0]));
}
deinterleave_input_samples(s, samples, planar_samples);
/* apply MDCT */
for (ch = 0; ch < s->channels; ch++) {