Initial pile-audio

crates/pile-audio/tests/files/flac_uncommon/README.md

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+# Group uncommon
+
+Certain features of the FLAC format are non-subset or otherwise
+uncommonly used. Decoders might not be able to playback these
+files, but they should detect this inability and preferably
+notify the user rather than crash of freeze. Read the
+README.txt in the directory uncommon for details on each file.
+
+Note that despite the features being used are uncommon, these
+files are still valid FLAC files.
+
+
+## Manifest
+
+- File 01 has a sample rate that changes mid-stream. The file
+  starts with a sample rate of 32kHz and switches to 24kHz,
+  16kHz and finally 48kHz.
+
+- File 02 has a number of channels that increases mid-stream.
+  The file starts with 1 channel, changes to stereo and ends
+  with 6 channels.
+
+- File 03 has a number of channels decreases mid-stream. It
+  starts with 4 channels, changes to stereo and ends with
+  1 channel.
+
+- File 04 has a bit depth that changes mid-stream. It starts
+  with a bit depth of 16, changes to 8 and ends with 24.
+
+- File 05 has a bit depth of 32 bit per sample.
+
+- File 06 has a sample rate of 768kHz. Because this sample
+  rate cannot be described in the FLAC frame header, files
+  with this sample rate are not streamable and not subset.
+
+- File 07 has a bit depth of 15 bit per sample. Because this
+  bit depth cannot be described in the FLAC frame header,
+  files with this bit depth are not streamable and not subset.
+
+- File 08 has a block size of 65535 samples, which is the
+  largest possible block size in FLAC. File using such large
+  blocks are not subset.
+
+- File 09 has one subframe with a rice partition order of 15,
+  which is the highest possible partition order. In effect
+  it means each partition in that subframe contains only a
+  single sample. Such an extreme might trigger peculiar
+  behaviour in a decoder.
+
+- File 10 is a FLAC file that starts directly at a frame
+  header, which means the fLaC marker is absent and no
+  metadata is present either. While this is not a recommended
+  format to store audio data in, it simulates the way a FLAC
+  stream is received when multicast. Additionally, the frame
+  numbers of the frames in the stream are rather high which
+  can happen when streaming uninterrupted for a long time.
+
+- File 11 is similar in purpose to file 10, but this file has
+  unparsable data preceding the first FLAC frame header. This
+  better simulates receiving a multicast FLAC stream, because
+  the first received packet of a multicast stream might not
+  align with a frame boundary, as a frame might be split over
+  several packets.