This was the outcome of a conversation really. Way too long to give you a literal query.
I kinda accidentally stumbled into this project. At first I thought I'd come up with the best workflow and ask AI how I can automate it.
For years now I've found that search engines respond to questions, and so when I have a question, my starting point is to ask the search engine that. So that's how I've been treating AI, ask it a question, and see where that takes me.
And when it takes me to python code, then I can tell it what it did wrong, or copy paste the incorrect output, and it gives me a corrected version.
In this case, it started as a question of automating my workflow, which it tried to write a python script to do the whole thing, without understanding that it can't call on foobar to process or convert things from the command line (or if you can, we did it wrong and abandoned that), and once I reached the point of a successful .dsf extraction but it bombing out at the level checking, that's when I decided - break that off, save a working .dsf extract script, and lets build a separate script for checking levels.
And that was really the turning point when I realized what I had fallen into, and that I needed to build small scripts to call on. So the obvious next step was to build a python script to determine the gain.
I am trying to pour over this to give you specifics, but can't quite yet - but at some point the discussion was developing a script for the gain, and the AI was trying to do it using sox, and I pasted the error and that's when we determined sox can't process dsf files. So then it gave me a command to run to check levels using ffmpeg, which we tested on one track (we were still extracting .dsf tracks at that point) (ffmpeg -i "M:\Staging\SACDout\Stereo\In Deep & Nexus Pt 1\Stereo\01 - God Gave Rock and Roll to You.dsf" -af "astats=metadata=1:reset=1" -f null -) and it returned values that made no sense, Peak level dB: -22.294518, Peak level dB: -22.010158
Oh....then we ran into problems finding the files, because of the folder structure that sacd_extract.exe creates. In my staging folder (M:\Staging\SACDout) it created a Stereo folder for stereo output and Multichannel folder for multi out - but sacd_extract automatically will create in it's landing spot a folder for the disc, and a folder for the stereo, so I had these embedded folders I didn't want, that had names that would change, based on the disc name, and for multichannel based on number of channels (5ch or 6ch). So I asked it to build me a script that would move the files up to the parent folder and wipe those subfolders out. And then we got back to the gain issue.
After that - I asked it to clarify about a comment it made earlier about a fork of sox that could handle dsf - but I'll scroll past that, the outcome of that was I found a sox fork that gave me 0db readings for everything, so I abandoned that and restored the sox we had that doesn't deal with dsf.
So we were stuck, we had foobar that couldn't be called on to automate this process, we had ffmpeg giving us levels 16dB lower than we were expecting, and we had a sox fork that gave us 0dB level readings. (At some point I manually processed the files to determine the level we were looking for was -6.25 for L and -6.94 for R, and we confirmed that when using ffmpeg to convert the .dsf to wav that was the peak level we got, despite the -22 readings).
At this point Grok was suggesting an initial conversion to a temp .wav to check levels, then a new conversion with the gain value. Which I didn't like, because that's just automating extra steps we shouldn't need. So I asked it a question:
(finally, we get to an actual query)
Converting all our .dsf files to .wav as a reference to determine levels is a significant time waste when we should be able to read levels directly from the .dsf file. How come the DR Meter (foo_dr_meter) can accurately determine levels on a .dsf file without conversion, but we can't come up with a method?
And it responded:
You’re absolutely right—converting every .dsf to WAV just to check levels is inefficient and frustrating, especially when foobar2000’s DR Meter (foo_dynamic_range) can analyze .dsf files directly and give accurate peaks (-6.25/-6.94 dBFS) without any intermediate steps. It’s a fair question: why can’t we replicate that? The answer lies in how foobar2000 handles DSD internally versus the limitations of command-line tools like FFmpeg and SoX. Let’s break this down, figure out why DR Meter succeeds, and find a way to match it without conversions.
Why DR Meter Works Directly
- foobar2000 Architecture:
- Uses foo_input_sacd to decode .dsf files. This plugin converts DSD to PCM in real-time within foobar2000’s pipeline, applying a standard scaling (likely -6 dB SACD-to-PCM offset per SACD specs).
- DR Meter (foo_dynamic_range) then analyzes this PCM stream, measuring true peaks and RMS relative to 0 dBFS.
- Key Advantage: The conversion and analysis happen seamlessly in memory—no temp files, no external CLI. The plugin’s DSD-to-PCM process is tuned for SACD playback and analysis, ensuring peaks align with mastered levels (e.g., -6 dBFS).
Your Results
- .dsf in foobar2000:
- Peak: -6.25 dBFS (Left), -6.94 dBFS (Right)
- RMS: -20.30 dB (Left), -20.84 dB (Right)
- Trusted benchmark we need to match.
Why CLI Tools Struggle
- FFmpeg:
- Decodes .dsf to PCM correctly (proven by WAV output matching foobar2000), but the astats filter reports peaks at -22 dBFS—16 dB too low.
- Likely issue: astats misreferences the PCM scale or applies an undocumented attenuation for DSD’s noise floor, despite the raw PCM being correct.
- SoX (Original 14.4.2):
- No .dsf support—fails outright.
- SoX DSD Fork:
- Reads .dsf but normalizes to 0 dBFS, misinterpreting DSD levels entirely.
- Common Problem:
- CLI tools lack foobar2000’s integrated DSD handling. They either don’t support .dsf natively or mishandle the DSD-to-PCM scaling in analysis mode.
How DR Meter Does It
- Source Insight: foo_input_sacd (open-source on GitHub: https://github.com/dkrey/foo_input_sacd) uses a DSD-to-PCM converter with a fixed gain (typically -6 dB) to map 0 dB SACD to -6 dBFS PCM, avoiding clipping while preserving signal integrity.
- DR Meter: Written by Peter Pawlowski (foobar2000’s creator), it hooks into this PCM stream post-conversion, using a precise peak detection algorithm (likely ReplayGain-based) to report dBFS levels.
- No Files: All processing is in-memory, leveraging foobar2000’s playback chain.
Why We Can’t Call It Directly
- Foobar2000 v1.6.16 CLI doesn’t expose DR Meter or foo_input_sacd analysis via command line. Components like foo_run can trigger playback commands, but not export peak data.
Finding a Direct .dsf Solution
We need a CLI tool or method that:
- Reads .dsf natively.
- Converts DSD to PCM with the same scaling as foo_input_sacd (-6 dB offset).
- Reports accurate peaks without temp files.
Option 1: Reverse-Engineer foo_input_sacd
- Idea: Use its DSD decoding logic standalone.
- Reality: Requires compiling the plugin’s C++ code into a CLI tool—complex and time-intensive (needs Visual Studio, audio libs).
Option 2: FFmpeg with Correct Scaling
- Discovery: FFmpeg’s WAV output matches foobar2000, but astats doesn’t. Can we fix astats or bypass it?
- Test: Analyze FFmpeg’s PCM output directly without astats:
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ffmpeg -i "M:\Staging\SACDout\Stereo\01 - God Gave Rock and Roll to You.dsf" -f f32le -ar 88200 - | sox -t raw -r 88200 -e float -b 32 -c 2 - -n stats
- -f f32le: Outputs raw 32-bit float PCM.
- Pipes to SoX for stats on the fly (no WAV file).
- Test Request:
- Run the command above.
- Share SoX’s Pk lev dB output.
- Tell me: “I tested FFmpeg pipe to SoX. Peaks were [X dBFS].”
Option 3: Alternative CLI Tool
- dsdinfo: A lightweight DSD analyzer (from sacd-ripper tools).
- Limited availability, no peak level output—mostly metadata.
- libsndfile CLI: sndfile-info reads .dsf with recent builds, but no peak analysis.
- Verdict: None match DR Meter’s precision out of the box.
Why Option 2 Might Work
- FFmpeg’s DSD-to-PCM decoding is correct (WAV test proved it).
- Piping raw PCM to SoX avoids astats’s scaling issue and temp files.
- SoX’s stats on PCM should match foobar2000 if the pipe preserves levels.
Expected Output
- Pk lev dB around -6.25/-6.94 dBFS for Left/Right, aligning with DR Meter.
Next Steps
- Run the Test:
- Try the FFmpeg-to-SoX pipe command.
- Share the SoX output.
- If It Works:
- I’ll script analyze_peaks.py to pipe all .dsf files this way.
- If Not:
- We’ll explore scripting foobar2000 with a component (e.g., foo_run + log output) or accept the WAV conversion trade-off.
You’re right—we should read .dsf directly like DR Meter. This pipe test could be our breakthrough—run it and let me know the results!
After a little troubleshooting to deal with a .dll issue with sox, we had a successful test with the option 2 command
E:\iso2dsd>ffmpeg -i "M:\Staging\SACDout\Stereo\01 - God Gave Rock and Roll to You.dsf" -f f32le -ar 88200 - | "C:\Program Files (x86)\sox-14-4-2\sox.exe" -t raw -r 88200 -e float -b 32 -c 2 - -n stats
ffmpeg version 7.1-full_build-www.gyan.dev Copyright (c) 2000-2024 the FFmpeg developers built with gcc 14.2.0 (Rev1, Built by MSYS2 project) configuration: --enable-gpl --enable-version3 --enable-static --disable-w32threads --disable-autodetect --enable-fontconfig --enable-iconv --enable-gnutls --enable-libxml2 --enable-gmp --enable-bzlib --enable-lzma --enable-libsnappy --enable-zlib --enable-librist --enable-libsrt --enable-libssh --enable-libzmq --enable-avisynth --enable-libbluray --enable-libcaca --enable-sdl2 --enable-libaribb24 --enable-libaribcaption --enable-libdav1d --enable-libdavs2 --enable-libopenjpeg --enable-libquirc --enable-libuavs3d --enable-libxevd --enable-libzvbi --enable-libqrencode --enable-librav1e --enable-libsvtav1 --enable-libvvenc --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxavs2 --enable-libxeve --enable-libxvid --enable-libaom --enable-libjxl --enable-libvpx --enable-mediafoundation --enable-libass --enable-frei0r --enable-libfreetype --enable-libfribidi --enable-libharfbuzz --enable-liblensfun --enable-libvidstab --enable-libvmaf --enable-libzimg --enable-amf --enable-cuda-llvm --enable-cuvid --enable-dxva2 --enable-d3d11va --enable-d3d12va --enable-ffnvcodec --enable-libvpl --enable-nvdec --enable-nvenc --enable-vaapi --enable-libshaderc --enable-vulkan --enable-libplacebo --enable-opencl --enable-libcdio --enable-libgme --enable-libmodplug --enable-libopenmpt --enable-libopencore-amrwb --enable-libmp3lame --enable-libshine --enable-libtheora --enable-libtwolame --enable-libvo-amrwbenc --enable-libcodec2 --enable-libilbc --enable-libgsm --enable-liblc3 --enable-libopencore-amrnb --enable-libopus --enable-libspeex --enable-libvorbis --enable-ladspa --enable-libbs2b --enable-libflite --enable-libmysofa --enable-librubberband --enable-libsoxr --enable-chromaprint libavutil 59. 39.100 / 59. 39.100 libavcodec 61. 19.100 / 61. 19.100 libavformat 61. 7.100 / 61. 7.100 libavdevice 61. 3.100 / 61. 3.100 libavfilter 10. 4.100 / 10. 4.100 libswscale 8. 3.100 / 8. 3.100 libswresample 5. 3.100 / 5. 3.100 libpostproc 58. 3.100 / 58. 3.100[dsf @ 000002d3638d97c0] Estimating duration from bitrate, this may be inaccurateInput #0, dsf, from 'M:\Staging\SACDout\Stereo\01 - God Gave Rock and Roll to You.dsf': Metadata: title : God Gave Rock and Roll to You album : In Deep & Nexus Pt 1 artist : Argent album_artist : Argent PERFORMER : Argent composer : Ballard TSRC : USSM17300809 publisher : Vocalion Ltd copyright : Sony Music disc : 1/1 genre : R&B track : 1/13 date : 2019-17-11 Duration: 00:06:43.91, start: 0.000000, bitrate: 5644 kb/s Stream #0:0: Audio: dsd_lsbf_planar, 352800 Hz, stereo, fltp, 5644 kb/sStream mapping: Stream #0:0 -> #0:0 (dsd_lsbf_planar (native) -> pcm_f32le (native))Press [q] to stop, [?] for helpOutput #0, f32le, to 'pipe:': Metadata: title : God Gave Rock and Roll to You album : In Deep & Nexus Pt 1 artist : Argent album_artist : Argent PERFORMER : Argent composer : Ballard TSRC : USSM17300809 publisher : Vocalion Ltd copyright : Sony Music disc : 1/1 genre : R&B track : 1/13 date : 2019-17-11 encoder : Lavf61.7.100 Stream #0:0: Audio: pcm_f32le, 88200 Hz, stereo, flt, 5644 kb/s Metadata: encoder : Lavc61.19.100 pcm_f32le[out#0/f32le @ 000002d3638ebb80] video:0KiB audio:278317KiB subtitle:0KiB other streams:0KiB global headers:0KiB muxing overhead: 0.000000%size= 278317KiB time=00:06:43.90 bitrate=5644.8kbits/s speed= 117x Overall Left RightDC offset -0.000000 -0.000000 -0.000000Min level -0.457259 -0.457259 -0.419144Max level 0.486967 0.486967 0.449288Pk lev dB -6.25 -6.25 -6.95RMS lev dB -23.55 -23.29 -23.83RMS Pk dB -16.75 -16.87 -16.75RMS Tr dB -80.74 -77.80 -80.74Crest factor - 7.12 6.98Flat factor 0.00 0.00 0.00Pk count 2 2 2Bit-depth 31/32 31/32 31/32Num samples 35.6MLength s 403.907Scale max 1.000000Window s 0.050
Which included peak values we expected to see of -6.25 and -6.95 (just a little off of the -6.94 from our test, but within a margin of error)
And then it wrote me the first version of the script I pasted above.