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Diffstat (limited to '')
-rw-r--r-- | src/pcm/FallbackResampler.cxx | 147 |
1 files changed, 147 insertions, 0 deletions
diff --git a/src/pcm/FallbackResampler.cxx b/src/pcm/FallbackResampler.cxx new file mode 100644 index 000000000..120b3fbdf --- /dev/null +++ b/src/pcm/FallbackResampler.cxx @@ -0,0 +1,147 @@ +/* + * Copyright (C) 2003-2014 The Music Player Daemon Project + * http://www.musicpd.org + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License along + * with this program; if not, write to the Free Software Foundation, Inc., + * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. + */ + +#include "config.h" +#include "FallbackResampler.hxx" + +#include <assert.h> + +AudioFormat +FallbackPcmResampler::Open(AudioFormat &af, unsigned new_sample_rate, + gcc_unused Error &error) +{ + assert(af.IsValid()); + assert(audio_valid_sample_rate(new_sample_rate)); + + switch (af.format) { + case SampleFormat::UNDEFINED: + assert(false); + gcc_unreachable(); + + case SampleFormat::S8: + af.format = SampleFormat::S16; + break; + + case SampleFormat::S16: + case SampleFormat::FLOAT: + case SampleFormat::S24_P32: + case SampleFormat::S32: + break; + + case SampleFormat::DSD: + af.format = SampleFormat::FLOAT; + break; + } + + format = af; + out_rate = new_sample_rate; + + AudioFormat result = af; + result.sample_rate = new_sample_rate; + return result; +} + +void +FallbackPcmResampler::Close() +{ +} + +template<typename T> +static ConstBuffer<T> +pcm_resample_fallback(PcmBuffer &buffer, + unsigned channels, + unsigned src_rate, + ConstBuffer<T> src, + unsigned dest_rate) +{ + unsigned dest_pos = 0; + unsigned src_frames = src.size / channels; + unsigned dest_frames = + (src_frames * dest_rate + src_rate - 1) / src_rate; + unsigned dest_samples = dest_frames * channels; + size_t dest_size = dest_samples * sizeof(*src.data); + T *dest_buffer = (T *)buffer.Get(dest_size); + + assert((src.size % channels) == 0); + + switch (channels) { + case 1: + while (dest_pos < dest_samples) { + unsigned src_pos = dest_pos * src_rate / dest_rate; + + dest_buffer[dest_pos++] = src.data[src_pos]; + } + break; + case 2: + while (dest_pos < dest_samples) { + unsigned src_pos = dest_pos * src_rate / dest_rate; + src_pos &= ~1; + + dest_buffer[dest_pos++] = src.data[src_pos]; + dest_buffer[dest_pos++] = src.data[src_pos + 1]; + } + break; + } + + return { dest_buffer, dest_samples }; +} + +template<typename T> +static ConstBuffer<void> +pcm_resample_fallback_void(PcmBuffer &buffer, + unsigned channels, + unsigned src_rate, + ConstBuffer<void> src, + unsigned dest_rate) +{ + const auto typed_src = ConstBuffer<T>::FromVoid(src); + return pcm_resample_fallback(buffer, channels, src_rate, typed_src, + dest_rate); +} + +ConstBuffer<void> +FallbackPcmResampler::Resample(ConstBuffer<void> src, gcc_unused Error &error) +{ + switch (format.format) { + case SampleFormat::UNDEFINED: + case SampleFormat::S8: + case SampleFormat::DSD: + assert(false); + gcc_unreachable(); + + case SampleFormat::S16: + return pcm_resample_fallback_void<int16_t>(buffer, + format.channels, + format.sample_rate, + src, + out_rate); + + case SampleFormat::FLOAT: + case SampleFormat::S24_P32: + case SampleFormat::S32: + return pcm_resample_fallback_void<int32_t>(buffer, + format.channels, + format.sample_rate, + src, + out_rate); + } + + assert(false); + gcc_unreachable(); +} |