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Userland+LibAudio: Make audio applications support dynamic sample rate

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All audio applications (aplay, Piano, Sound Player) respect the ability
of the system to have theoretically any sample rate. Therefore, they
resample their own audio into the system sample rate.

LibAudio previously had its loaders resample their own audio, even
though they expose their sample rate. This is now changed. The loaders
output audio data in their file's sample rate, which the user has to
query and resample appropriately. Resampling code from Buffer, WavLoader
and FlacLoader is removed.

Note that these applications only check the sample rate at startup,
which is reasonable (the user has to restart applications when changing
the sample rate). Fully dynamic adaptation could both lead to errors and
will require another IPC interface. This seems to be enough for now.
This commit is contained in:
kleines Filmröllchen 2021-08-19 00:13:26 +02:00 • committed by Ali Mohammad Pur
parent 9880a5c481
commit d049626f40
12 changed files with 56 additions and 41 deletions
Download patch file Download diff file Expand all files Collapse all files

43
Userland/Libraries/LibAudio/Buffer.cpp
View file

@ -45,7 +45,7 @@ i32 Buffer::allocate_id()
}
template<typename SampleReader>
static void read_samples_from_stream(InputMemoryStream& stream, SampleReader read_sample, Vector<Frame>& samples, ResampleHelper<double>& resampler, int num_channels)
static void read_samples_from_stream(InputMemoryStream& stream, SampleReader read_sample, Vector<Frame>& samples, int num_channels)
{
double norm_l = 0;
double norm_r = 0;
@ -53,29 +53,23 @@ static void read_samples_from_stream(InputMemoryStream& stream, SampleReader rea
switch (num_channels) {
case 1:
for (;;) {
while (resampler.read_sample(norm_l, norm_r)) {
samples.append(Frame(norm_l));
}
norm_l = read_sample(stream);
samples.append(Frame(norm_l));
if (stream.handle_any_error()) {
break;
}
resampler.process_sample(norm_l, norm_r);
}
break;
case 2:
for (;;) {
while (resampler.read_sample(norm_l, norm_r)) {
samples.append(Frame(norm_l, norm_r));
}
norm_l = read_sample(stream);
norm_r = read_sample(stream);
samples.append(Frame(norm_l, norm_r));
if (stream.handle_any_error()) {
break;
}
resampler.process_sample(norm_l, norm_r);
}
break;
default:
@ -128,32 +122,32 @@ static double read_norm_sample_8(InputMemoryStream& stream)
return double(sample) / NumericLimits<u8>::max();
}
RefPtr<Buffer> Buffer::from_pcm_data(ReadonlyBytes data, ResampleHelper<double>& resampler, int num_channels, PcmSampleFormat sample_format)
RefPtr<Buffer> Buffer::from_pcm_data(ReadonlyBytes data, int num_channels, PcmSampleFormat sample_format)
{
InputMemoryStream stream { data };
return from_pcm_stream(stream, resampler, num_channels, sample_format, data.size() / (pcm_bits_per_sample(sample_format) / 8));
return from_pcm_stream(stream, num_channels, sample_format, data.size() / (pcm_bits_per_sample(sample_format) / 8));
}
RefPtr<Buffer> Buffer::from_pcm_stream(InputMemoryStream& stream, ResampleHelper<double>& resampler, int num_channels, PcmSampleFormat sample_format, int num_samples)
RefPtr<Buffer> Buffer::from_pcm_stream(InputMemoryStream& stream, int num_channels, PcmSampleFormat sample_format, int num_samples)
{
Vector<Frame> fdata;
fdata.ensure_capacity(num_samples);
switch (sample_format) {
case PcmSampleFormat::Uint8:
read_samples_from_stream(stream, read_norm_sample_8, fdata, resampler, num_channels);
read_samples_from_stream(stream, read_norm_sample_8, fdata, num_channels);
break;
case PcmSampleFormat::Int16:
read_samples_from_stream(stream, read_norm_sample_16, fdata, resampler, num_channels);
read_samples_from_stream(stream, read_norm_sample_16, fdata, num_channels);
break;
case PcmSampleFormat::Int24:
read_samples_from_stream(stream, read_norm_sample_24, fdata, resampler, num_channels);
read_samples_from_stream(stream, read_norm_sample_24, fdata, num_channels);
break;
case PcmSampleFormat::Float32:
read_samples_from_stream(stream, read_float_sample_32, fdata, resampler, num_channels);
read_samples_from_stream(stream, read_float_sample_32, fdata, num_channels);
break;
case PcmSampleFormat::Float64:
read_samples_from_stream(stream, read_float_sample_64, fdata, resampler, num_channels);
read_samples_from_stream(stream, read_float_sample_64, fdata, num_channels);
break;
default:
VERIFY_NOT_REACHED();
@ -193,6 +187,21 @@ Vector<SampleType> ResampleHelper<SampleType>::resample(Vector<SampleType> to_re
template Vector<i32> ResampleHelper<i32>::resample(Vector<i32>);
template Vector<double> ResampleHelper<double>::resample(Vector<double>);
NonnullRefPtr<Buffer> resample_buffer(ResampleHelper<double>& resampler, Buffer const& to_resample)
{
Vector<Frame> resampled;
resampled.ensure_capacity(to_resample.sample_count() * ceil_div(resampler.source(), resampler.target()));
for (size_t i = 0; i < static_cast<size_t>(to_resample.sample_count()); ++i) {
auto sample = to_resample.samples()[i];
resampler.process_sample(sample.left, sample.right);
while (resampler.read_sample(sample.left, sample.right))
resampled.append(sample);
}
return Buffer::create_with_samples(move(resampled));
}
template<typename SampleType>
void ResampleHelper<SampleType>::process_sample(SampleType sample_l, SampleType sample_r)
{