I have a large CD collection that I'd like to rip to a digital format for my phone

I don't think I have room for everything on my phone if I use FLAC, so I'd like to use a lossy format, with a high enough bitrate that I wouldn't be able to tell the difference between it and lossless on cheap-but-decent headphones (superlux HD681)

Which format can be near-indistinguishable from lossless CD audio at the lowest bitrate? Google seems to suggest mp3@320kbps is generally considered good enough, but can you go lower (say 250) with more advanced codecs like aac or ogg? Or does the extra complexity only give a benefit for mediocre quality at a lower bitrate?

I know this is subjective and there's always a diminishing return, but I'd like advice from someone who is more of an audiophile than I am about where to draw the line.

Also any recommendations for software or encoders that do a good job of the compression without losing metadata would be much appreciated.

  • 1
    Re your last point. CDs don't have any metadata at all. The info is grabbed online using a fingerprint system at rip & embedded.
    – Tetsujin
    Apr 30, 2022 at 12:58
  • Good point (other than cd-text which is inconsistent and generally lacking in my experience) - so either something that finds consistent metadata, or that doesn't lose anything when converting from a temporary intermediate wav file that's got decent metadata from elsewhere
    – sqek
    Apr 30, 2022 at 22:43
  • I recently have made some comparisons for MP3 compression. See replayer.app/en/blog/… for the results. If it's for personal use, try some levels and see what is good enough for your ears.
    – Marcel
    May 2, 2022 at 10:32
  • tbh, for a phone, 128bit AAC [or MP3 if it doesn't support AAC] is plenty good enough. The DACs won't really be good for much more & headphones/earbuds or a car player certainly won't.
    – Tetsujin
    May 3, 2022 at 18:01
  • @Tetsujin Depends massively on the phone - my previous Huawei was terrible and couldn't drive most over-ear headphones at reasonable volume without weird artefacts (not normal clipping, more like a power supply not being able to keep up and intermittently dropping) But my current Cubot will happily power my 2x32ohm superlux hd681s louder than I'd like, and I could reliably tell opus 128kbps from 144 by playing a few seconds of each file side-by-side (blindly, then checking) - I think because it's a bit thicker so they had room to put some proper caps etc
    – sqek
    May 4, 2022 at 9:54

2 Answers 2


Opus is sort of the highest-quality codec at a given bitrate these days. Problem is that "phones", while certainly having the Opus codec for various things (webm format, video conferencing) tend to have a dim view towards its "canonical" packaging in ogg containers. What I do is to convert into a webm format instead ("for" VP9) but omit the video track (the actual VP9 encoded part). Most multi-media players on phones as well as proprietary systems are fine with playing this video format with audio without video. The container format in this case is not ogg (as it would be with "canonical" Opus files) but Matroska.

Note that the "VP8"-based older webm format does not use Opus but Vorbis for its audio, meaning that it is less efficient than the "VP9" version.

For most purposes 192kbps or even less should work fine (as in "essentially indistinguishable from the real thing for most people and most music") with Opus.

  • Brilliant, thank you! I hadn't heard of opus before. And it looks like it's natively supported from android 10 onwards with a .opus extension (googling says most players assume vorbis for ogg files, so for android 10+ .opus works better), so I'll try downloading audio players until one works, otherwise try your webm trick if I can't find a good one
    – sqek
    May 1, 2022 at 10:34
  • Opus seems to be working well - I can just about tell 128kbps from 144 in an A/B test, can't tell 144 from 192 - so noticeably smaller than 320kbps mp3s. .opus extensions don't get indexed by android's players, but opus with a .ogg extension works on newer androids works. CUEtools/CUEripper seems to be good at finding metadata, rips and encodes nicely, and doesn't need too many clicks per CD
    – sqek
    May 2, 2022 at 11:35

I took a multi-step approach:

  1. I have ripped my CD's to WAV or FLAC, which are both lossless formats. I store these on my Network Attached Storage (NAS) where I have plenty of space.

  2. Now for listening in the car or on the phone, I converted each track to an MP3 file, with my compression level of choice.

  3. I just copy over the the tracks I intent to listen onto the device.

About the format and compression level, they depend on compatibility and your preferences mostly. MP3 220-260k VBR gives good results, especially when you plan to listen in a noisy environment or on sub-par equipment anyway.

Note: I have created (bash) scripts for each of these steps. Ask about these on SuperUser. There is plenty of information around.

Note2: ffmpeg is the tool I would recommend to do the conversion. See https://ffmpeg.org/ They have examples and again, ask on SuperUser, if you have a specific question about it.

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