From 192f65a56bc20a4539e7a0132cdec8b1e2fbc157 Mon Sep 17 00:00:00 2001
From: Laurent le Beau-Martin <1180863+laurentlbm@users.noreply.github.com>
Date: Wed, 9 Mar 2022 23:06:56 -0500
Subject: [PATCH] Improve ffmpeg command to transcode flac (#99)

* Improve ffmpeg command to transcode flac

The command previously suggested forced the output sample rate to 48 kHz, even if the input was lower, at 44.1 kHz.
This new command lets `ffmpeg` select the appropriate output sample rate to minimize conversion.
Documentation: https://www.ffmpeg.org/ffmpeg-filters.html#aformat-1

* Update transcoding command

- Support more sample rates and bit depths.
- Add note about S1
---
 README.md | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/README.md b/README.md
index 50196ce..ca3c284 100644
--- a/README.md
+++ b/README.md
@@ -209,10 +209,16 @@ In this case you could set;
 BNB_SUBSONIC_CUSTOM_CLIENTS="audio/flac"
 ```
 
-This would result in 2 players in Navidrome, one called 'bonob', the other called 'bonob+audio/flac'.  You could then configure a custom flac transcoder in Navidrome that re-samples the flacs to a sonos supported format, ie [Using something like this](https://stackoverflow.com/questions/41420391/ffmpeg-flac-24-bit-96khz-to-16-bit-48khz);
+This would result in 2 players in Navidrome, one called 'bonob', the other called 'bonob+audio/flac'.  You could then configure a custom flac transcoder in Navidrome that re-samples the flacs to a sonos supported format, ie [Using something like this](https://stackoverflow.com/questions/41420391/ffmpeg-flac-24-bit-96khz-to-16-bit-48khz) or [this](https://stackoverflow.com/questions/52119489/ffmpeg-limit-audio-sample-rate):
 
 ```bash
-ffmpeg -i %s -af aresample=resampler=soxr:out_sample_fmt=s16:out_sample_rate=48000 -f flac -
+ffmpeg -i %s -af aformat=sample_fmts=s16|s32:sample_rates=8000|11025|16000|22050|24000|32000|44100|48000 -f flac -
+```
+
+**Note for Sonos S1:** [24-bit depth is only supported by Sonos S2](https://support.sonos.com/s/article/79?language=en_US), so if your system is still on Sonos S1, transcoding should convert all FLACs to 16-bit:
+
+```bash
+ffmpeg -i %s -af aformat=sample_fmts=s16:sample_rates=8000|11025|16000|22050|24000|32000|44100|48000 -f flac -
 ```
 
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