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context: avoid excessive upsampling

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For lower than default rates, limit the upsampling to 2 times the default
rate. This avoid 8000Hz to the upsampled to 192000 when a 44100 is
available (but not 48000).
For higher rates limit the upsampling to *3.
This commit is contained in:
Wim Taymans 2023-01-27 18:16:23 +01:00
parent a5b2282b14
commit 3208946a5f
1 changed files with 30 additions and 6 deletions
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36
src/pipewire/context.c
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@ -1001,10 +1001,16 @@ static inline void update_nearest_gcd(struct rate_info *best, struct rate_info *
(best->gcd == current->gcd && best->diff > current->diff))
*best = *current;
}
static uint32_t find_best_rate(const uint32_t *rates, uint32_t n_rates, uint32_t rate, uint32_t current)
static inline void update_nearest_rate(struct rate_info *best, struct rate_info *current)
{
uint32_t i;
/* find nearest rate */
if (best->rate == 0 || best->diff > current->diff)
*best = *current;
}
static uint32_t find_best_rate(const uint32_t *rates, uint32_t n_rates, uint32_t rate, uint32_t def)
{
uint32_t i, limit;
struct rate_info best;
struct rate_info info[n_rates];
@ -1021,18 +1027,36 @@ static uint32_t find_best_rate(const uint32_t *rates, uint32_t n_rates, uint32_t
* 44100 and [ 32000 56000 88200 96000 ] -> 88200
* 48000 and [ 32000 56000 88200 96000 ] -> 96000
* 88200 and [ 44100 48000 96000 192000 ] -> 96000
* 32000 and [ 44100 192000 ] -> 44100
* 8000 and [ 44100 48000 ] -> 48000
* 8000 and [ 44100 192000 ] -> 44100
* 11025 and [ 44100 48000 ] -> 44100
* 44100 and [ 48000 176400 ] -> 48000
*/
spa_zero(best);
/* Don't try to do excessive upsampling by limiting the max rate
* for desired < default to default*2. For other rates allow
* a x3 upsample rate max */
limit = rate < def ? def*2 : rate*3;
for (i = 0; i < n_rates; i++) {
if (info[i].rate >= rate && info[i].rate <= limit)
update_nearest_gcd(&best, &info[i]);
}
if (best.rate != 0)
return best.rate;
/* we would need excessive upsampling, pick a nearest higher rate */
spa_zero(best);
for (i = 0; i < n_rates; i++) {
if (info[i].rate >= rate)
update_nearest_gcd(&best, &info[i]);
update_nearest_rate(&best, &info[i]);
}
if (best.rate != 0)
return best.rate;
/* There is nothing above the rate, we need to downsample. Try to downsample
* but only to something that is from a common rate family. Also don't
* try to downsample to something that will sound worse.
* try to downsample to something that will sound worse (< 44100).
*
* 88200 and [ 22050 44100 48000 ] -> 44100
* 88200 and [ 22050 48000 ] -> 48000
@ -1053,7 +1077,7 @@ static uint32_t find_best_rate(const uint32_t *rates, uint32_t n_rates, uint32_t
if (best.rate != 0)
return best.rate;
return current;
return def;
}
/* here we evaluate the complete state of the graph.