stream. The old syntax (e.g., "ff 30-") is still supported but it
is deprecated and no longer documented. The compatibility code is
sheduled for removal after 0.7.0.
-
- para_afh: New option: --preserve to reset the modification time to
the value of the original file after meta data modification.
+- Overhaul of the compress filter code. The refined algorithm should
+ reduce clipping. The meaning of --aggressiveness has changed, see the
+ updated and extended documentation of the compress filter for details.
--------------------------------------
0.6.2 (2018-06-30) "elastic diversity"
size_t length, i;
int16_t *ip, *op;
uint32_t inertia = U32_OPTVAL(INERTIA, fn->lpr);
- unsigned gain_shift = inertia + U32_OPTVAL(DAMP, fn->lpr),
- mask = (1U << U32_OPTVAL(BLOCKSIZE, fn->lpr)) - 1U;
+ unsigned mask = (1U << U32_OPTVAL(BLOCKSIZE, fn->lpr)) - 1U;
//inplace = false;
next_buffer:
ret = btr_node_status(btrn, fn->min_iqs, BTR_NT_INTERNAL);
neg = true;
}
sample *= pcd->current_gain;
- sample >>= gain_shift;
+ sample >>= inertia + 1;
if (sample > 32767) { /* clip */
+ PARA_WARNING_LOG("clip: %d\n", sample);
sample = 32767;
pcd->current_gain = (3 * pcd->current_gain +
(1 << inertia)) / 4;
pcd->peak = 0;
} else if (sample > pcd->peak)
pcd->peak = sample;
+ sample >>= U32_OPTVAL(DAMP, fn->lpr);
op[i] = neg? -sample : sample;
if (++pcd->num_samples & mask)
continue;
// PARA_DEBUG_LOG("gain: %u, peak: %u\n", pcd->current_gain,
// pcd->peak);
+
if (pcd->peak < U32_OPTVAL(TARGET_LEVEL, fn->lpr)) {
if (pcd->current_gain < pcd->max_gain)
pcd->current_gain++;
fn->private_data = pcd;
fn->min_iqs = 2; /* 16 bit audio */
pcd->current_gain = 1U << inertia;
- pcd->max_gain = 1U << (inertia + aggressiveness);
+ pcd->max_gain = (1U << inertia) * (1.0 + 3.0 * aggressiveness / 10.0);
+}
+
+static void *compress_setup(const struct lls_parse_result *lpr)
+{
+ uint32_t val;
+
+ val = U32_OPTVAL(BLOCKSIZE, lpr);
+ if (val == 0 || val > 31) {
+ PARA_EMERG_LOG("blocksize (%u) out of range\n", val);
+ exit(EXIT_FAILURE);
+ }
+ val = U32_OPTVAL(AGGRESSIVENESS, lpr);
+ if (val > 10) {
+ PARA_EMERG_LOG("aggressiveness (%u) out of range\n", val);
+ exit(EXIT_FAILURE);
+ }
+ val = U32_OPTVAL(INERTIA, lpr);
+ if (val == 0 || val > 14) {
+ PARA_EMERG_LOG("inertia (%u) out of range\n", val);
+ exit(EXIT_FAILURE);
+ }
+ val = U32_OPTVAL(TARGET_LEVEL, lpr);
+ if (val > 32767) {
+ PARA_EMERG_LOG("target-level (%u) out of range\n", val);
+ exit(EXIT_FAILURE);
+ }
+ val = U32_OPTVAL(DAMP, lpr);
+ if (val > 16) {
+ PARA_EMERG_LOG("damp (%u) out of range\n", val);
+ exit(EXIT_FAILURE);
+ }
+ return NULL; /* no need for a config structure */
}
const struct filter lsg_filter_cmd_com_compress_user_data = {
+ .setup = compress_setup,
.open = compress_open,
.close = compress_close,
.pre_select = generic_filter_pre_select,
purpose = dynamically adjust the volume of an audio stream
[option blocksize]
short_opt = b
- summary = use blocks of size 2**bits
+ summary = adjust volume after each block of size 2**bits (1-31)
typestr = bits
arg_info = required_arg
arg_type = uint32
[/help]
[option aggressiveness]
short_opt = a
- summary = controls the maximum amount to amplify by
+ summary = controls the maximum amount to amplify by (0-10)
typestr = bits
arg_info = required_arg
arg_type = uint32
default_val = 4
+ [help]
+ This controls the maximal gain factor. Zero means to not amplify
+ at all while the value 10 corresponds to maximal gain factor which
+ results in a 4-fold increase in volume.
+ [/help]
[option inertia]
short_opt = i
- summary = how much inertia ramping has
+ summary = how much inertia ramping has (1-14)
typestr = bits
arg_info = required_arg
arg_type = uint32
default_val = 6
+ [help]
+ Larger values cause smaller volume adjustments.
+ [/help]
[option target-level]
short_opt = t
- summary = target signal level (0-32768)
+ summary = target signal level (0-32767)
typestr = level
arg_info = required_arg
arg_type = uint32
- default_val = 20000
+ default_val = 16384
+ [help]
+ If the peak of the previous block is less than the target level,
+ volume is increased slightly for the next block. Otherwise it is
+ decreased. The default value is chosen to minimize clipping. There
+ is usually no reason to change it.
+ [/help]
[option damp]
short_opt = d
- summary = if non-zero, scale down after normalizing
+ summary = if non-zero, scale down after normalizing (0-16)
typestr = bits
arg_info = required_arg
arg_type = uint32
default_val = 0
+ [help]
+ This scales down the volume of the audio stream by factor 2**bits.
+ This is mostly useful if another audio application (e.g., a video
+ game) is running in parallel and the relative volume of the audio
+ stream is too high.
+ [/help]
[subcommand fecdec]
purpose = decode a (lossy) input stream using forward error correction
[subcommand flacdec]