Split compute_bit_allocation() into 4 separate functions. Also, initialize
default bit alloc params in AC3_encode_init(). This will allow for other types
of bit allocation in the future.
---
libavcodec/ac3enc.c | 86 +++++++++++++++++++++++++++++----------------------
1 files changed, 49 insertions(+), 37 deletions(-)
diff --git libavcodec/ac3enc.c libavcodec/ac3enc.c
index 26058cf..8346f92 100644
--- libavcodec/ac3enc.c
+++ libavcodec/ac3enc.c
@@ -628,27 +628,9 @@ static int bit_alloc(AC3EncodeContext *s,
return 16 * s->frame_size - frame_bits;
}
-static int compute_bit_allocation(AC3EncodeContext *s,
- uint8_t bap[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS][AC3_MAX_COEFS],
- uint8_t encoded_exp[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS][AC3_MAX_COEFS],
- uint8_t exp_strategy[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS],
- int frame_bits)
+static void set_bit_alloc_params(AC3EncodeContext *s)
{
- int blk, ch;
- int snr_offset, snr_incr;
- uint8_t bap1[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS][AC3_MAX_COEFS];
- int16_t psd[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS][AC3_MAX_COEFS];
- int16_t mask[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS][50];
- static const int frame_bits_inc[8] = { 0, 0, 2, 2, 2, 4, 2, 4 };
-
- /* init default parameters */
- s->slow_decay_code = 2;
- s->fast_decay_code = 1;
- s->slow_gain_code = 1;
- s->db_per_bit_code = 2;
- s->floor_code = 4;
- for (ch = 0; ch < s->channels; ch++)
- s->fast_gain_code[ch] = 4;
+ /* TODO: modify bit allocation parameters */
/* compute real values */
s->bit_alloc.slow_decay = ff_ac3_slow_decay_tab[s->slow_decay_code] >> s->bit_alloc.sr_shift;
@@ -656,6 +638,14 @@ static int compute_bit_allocation(AC3EncodeContext *s,
s->bit_alloc.slow_gain = ff_ac3_slow_gain_tab[s->slow_gain_code];
s->bit_alloc.db_per_bit = ff_ac3_db_per_bit_tab[s->db_per_bit_code];
s->bit_alloc.floor = ff_ac3_floor_tab[s->floor_code];
+}
+
+static int count_frame_bits(AC3EncodeContext *s,
+ uint8_t exp_strategy[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS],
+ int frame_bits)
+{
+ int blk, ch;
+ static const int frame_bits_inc[8] = { 0, 0, 2, 2, 2, 4, 2, 4 };
/* header size */
frame_bits += 65;
@@ -694,11 +684,18 @@ static int compute_bit_allocation(AC3EncodeContext *s,
/* CRC */
frame_bits += 16;
- /* calculate psd and masking curve before doing bit allocation */
- bit_alloc_masking(s, encoded_exp, exp_strategy, psd, mask);
+ return frame_bits;
+}
- /* now the big work begins : do the bit allocation. Modify the snr
- offset until we can pack everything in the requested frame size */
+static int csnr_bit_alloc(AC3EncodeContext *s,
+ int16_t mask[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS][50],
+ int16_t psd[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS][AC3_MAX_COEFS],
+ uint8_t bap[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS][AC3_MAX_COEFS],
+ int frame_bits)
+{
+ int ch;
+ int snr_offset, snr_incr;
+ uint8_t bap1[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS][AC3_MAX_COEFS];
snr_offset = s->coarse_snr_offset << 4;
if ((snr_offset | s->fine_snr_offset[0]) == 1023)
@@ -722,22 +719,28 @@ static int compute_bit_allocation(AC3EncodeContext *s,
s->coarse_snr_offset = snr_offset >> 4;
for(ch=0;ch<s->channels;ch++)
s->fine_snr_offset[ch] = snr_offset & 0xF;
-#ifdef DEBUG_BITALLOC
- {
- int i;
- for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {
- for (ch = 0; ch < s->channels; ch++) {
- dprintf(s->avctx, "bap[blk=%d][ch=%d]=", blk, ch);
- for (i = 0; i < s->nb_coefs[ch]; i++)
- dprintf(s->avctx, "%d ",bap[blk][ch][i]);
- dprintf(s->avctx, "\n");
- }
- }
- }
-#endif
+
return 0;
}
+static int compute_bit_allocation(AC3EncodeContext *s,
+ uint8_t bap[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS][AC3_MAX_COEFS],
+ uint8_t encoded_exp[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS][AC3_MAX_COEFS],
+ uint8_t exp_strategy[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS],
+ int frame_bits)
+{
+ int16_t psd[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS][AC3_MAX_COEFS];
+ int16_t mask[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS][50];
+
+ set_bit_alloc_params(s);
+
+ frame_bits = count_frame_bits(s, exp_strategy, frame_bits);
+
+ bit_alloc_masking(s, encoded_exp, exp_strategy, psd, mask);
+
+ return csnr_bit_alloc(s, mask, psd, bap, frame_bits);
+}
+
static av_cold int set_channel_info(AC3EncodeContext *s, int channels,
int64_t *channel_layout)
{
@@ -857,6 +860,15 @@ static av_cold int AC3_encode_init(AVCodecContext *avctx)
/* initial snr offset */
s->coarse_snr_offset = 40;
+ /* default bit allocation parameters */
+ s->slow_decay_code = 2;
+ s->fast_decay_code = 1;
+ s->slow_gain_code = 1;
+ s->db_per_bit_code = 2;
+ s->floor_code = 4;
+ for (ch = 0; ch < s->channels; ch++)
+ s->fast_gain_code[ch] = 4;
+
mdct_init();
for (j = 0; j < 256; j++) {
_______________________________________________
FFmpeg-soc mailing list
[email protected]
https://lists.mplayerhq.hu/mailman/listinfo/ffmpeg-soc
