The number of samples is a critical aspect of IR. So we'll have to investigate if there are any additional frames being added after the encoding. Decoding also might introduce some artifacts in terms of number of samples.

Why would a lossless encoding introduce extra stuff?  That doesn't seem very lossless to me.

But we'll have to test to be sure, I guess.  I guess that also means a layout test to verify that the FLAC-encoded version matches the original WAV-encoded version exactly.

Adding few frames at the head and the tail for the sake of en/decoding is not losing something as far as you get the audible content correctly. That's the thing - we have to find out what 'lossless' actually means here.

For the record, I used avconv to convert the file to flac and then convert back to wav.  The resulting wav file is slightly longer, but the content is identical, according to octave.

So the additional frames after? or before? Also avconv might do something different from FFMPEG.

The actual file on disk is slightly longer.  The actual audio data is exactly the same length. I did not look, but I think the WAV header is slightly longer.

Ok. I stripped off the WAV header from each file and the result is that both files have exactly the same length and data.  avconv put in some additional header fields.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/625aefda371b1533682cf59b9332404a913651f4

commit 625aefda371b1533682cf59b9332404a913651f4
Author: rtoy <rtoy@chromium.org>
Date: Wed Dec 07 19:13:35 2016

Encode HRTF database using FLAC

Encoding the HRTF database using FLAC shrinks the database file from
245804 bytes to 145812 bytes (40% less space), while still keeping
exactly the same data.

BUG= 76391 ,  669545 
TEST=hrtf-database.html

Review-Url: https://codereview.chromium.org/2537183002
Cr-Commit-Position: refs/heads/master@{#437026}

[add] https://crrev.com/625aefda371b1533682cf59b9332404a913651f4/third_party/WebKit/LayoutTests/webaudio/hrtf-database.html
[modify] https://crrev.com/625aefda371b1533682cf59b9332404a913651f4/third_party/WebKit/LayoutTests/webaudio/resources/audit.js
[modify] https://crrev.com/625aefda371b1533682cf59b9332404a913651f4/third_party/WebKit/LayoutTests/webaudio/resources/buffer-loader.js
[add] https://crrev.com/625aefda371b1533682cf59b9332404a913651f4/third_party/WebKit/Source/platform/audio/resources/Composite.flac
[add] https://crrev.com/625aefda371b1533682cf59b9332404a913651f4/third_party/WebKit/Source/platform/audio/resources/README
[modify] https://crrev.com/625aefda371b1533682cf59b9332404a913651f4/third_party/WebKit/public/blink_resources.grd