Engine OS 5.x: Some FLAC files stop playing after about 2 seconds (Desktop & Standalone)

Engine DJ Software Engine DJ (Mac & PC)
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1

I have found what appears to be a separate bug affecting certain FLAC files.

So far, I have only found three examples in my library of around 12,000 tracks, so the issue seems to be quite rare. Two of those files were not important and have already been deleted, but one track has to remain because I still use it:

lifelike, Kris Menace - What Time Is Love (Live at SSL Mix).flac

The problem is that only the first two seconds of the track are played. After that, playback stops. This happens both in Engine DJ Desktop and on my Prime 4+ in standalone mode.

To narrow the issue down, I tried several conversions:

Original FLAC → playback stops after about 2 seconds. FLAC → MP3 → plays normally. FLAC → WAV → plays normally. WAV → FLAC (re-encoded with dBpoweramp) → the problem immediately returns.

The original FLAC file was also created using dBpoweramp, which is a well-established and standards-compliant FLAC encoder. Because the issue can be reproduced by converting the WAV back to FLAC, I suspect the problem is related to the FLAC decoding engine rather than the audio content itself.

Obviously, testing an entire library of 12,000 tracks for such a rare issue is almost impossible, but it is still frustrating when you discover it during a performance.

There is one additional observation that may help identify the cause:

If a Stems file exists for this track, the behaviour becomes even stranger. When I mute the Bass stem (Stem 4), I can hear the other three stems. If I mute those three stems and enable only the Bass stem, I hear only the bass.

Has anyone else come across FLAC files with similar behaviour?

2

What’s the bit depth of your FLAC files?

3

image
image385Ă—410 21 KB

4

Can you try to convert the file using a cloud service instead see if you get the same result.

5

The online converter fixed that one file.

However, it still doesn’t explain why Engine DJ and Engine OS refuse to play it in the first place.

Every other player I’ve tested handles the file without any issues, including VirtualDJ, Windows Media Player, and several others.

With a library of around 12,000 tracks, it’s simply not realistic to blindly convert everything just in case.

The important question is: what exactly is it about this FLAC file that Engine DJ and Engine OS don’t like?

If the developers can identify the specific part of the file or metadata that causes the decoder to fail, users could verify and fix only the affected files instead of having to re-encode an entire music collection.

6

Most of my files are FLAC with 600x600 artwork and haven’t experienced the issues. I don’t use dbPoweramp, but SoundForge to encode. Not saying it wouldn’t be the decoding of course.

7

So far, while looking for a different issue, I’ve only found three affected files.

I don’t want to make claims I can’t verify, but I’m pretty sure I’ve played the track before. However, it’s quite possible I played it in VirtualDJ rather than Engine OS, so I don’t want to blame the 5.x versions without proof. I think it’s more likely just a coincidence.

It’s not unusual for certain encoder/decoder combinations to produce files that have compatibility issues.

Is there actually a good alternative to dBpoweramp? I’ve been using it for about 12 years.

Re-encoding the files wouldn’t be a problem for VirtualDJ. With Engine DJ, I’d probably have to regenerate the stems afterwards, but that’s doable too.

8

The WAV format hasn’t got a “defined by standards” artwork placement. Depends on the editor. Converting those to FLAC should not be an issue either.

9

WAV isn’t an option for me; that was just a test. As you said, there are hardly any standards—if any at all—for WAV.

For me, FLAC is a must—not because of the sound quality; even on large PA systems at high volumes—or a good Hi-Fi setup—you’d hardly be able to distinguish it from 320 kb/s. (Just my opinion… :slight_smile: )

For me, it’s about cue shifting—an issue that definitely doesn’t happen with FLAC. Whether it’s VDJ, EngineDJ, RB, or Serato, all cues and loops are perfectly aligned.

So, I’d love some recommendations for a good FLAC converter that supports batch processing—ideally from someone who actually uses FLAC themselves.

10

Maybe if the track is mission critical for you, it’s worth having 2 format versions of it since you aren’t always using Engine DJ for playing out?? Just a thought…

11

Thanks for the suggestion.

Fortunately, no single track is mission-critical for me. For weddings or other events where I receive special requests, I always test those tracks beforehand. And in the unlikely event that something doesn’t play, I always have a suitable replacement ready.

The interesting part for me is that Engine OS is currently the only player I’ve found that refuses to play these files. Every other player I’ve tested handles them without any issues.

That’s why I’d really like to hear from the developers whether this is something worth investigating and whether they have any idea what characteristic of these FLAC files causes Engine OS to reject them.

It’s not a major issue for me personally, but if I’ve already found three affected files while testing for something completely different, there are almost certainly more out there. :slightly_smiling_face:

12

A couple of years ago a few AIFF I purchased from Beatport beat gridded and played fine in Engine Desktop, but the SC6000 said the files were corrupt or unsupported. First, I inspected for anomalous extended characters in the file paths, names and metadata…none. I ran them through X Lossless Decoder (XLD, Mac-only program) and converted AIFF to AIFF and then they played fine. When you prepare files in Engine DJ Desktop (or Lexicon), if you want to be sure, you still need to check each one with Engine OS on the units.

That’s the right attitude, especially when dealing with a lot of legacy digital files.

13

Defeats the whole purpose of Engine DJ Desktop, doesn’t it?

Also, even my car’s headunit does not have these issues with playback stability, it simply skips the tracks it cannot read properly.

14

I had the same experience, but only with one track in my collection. So far… Then again I only have about 6000 tracks in my database. Round about two years ago, I bought an album on Bandcamp and downloaded the flac encoding, as always. One of the tracks on that album would play fine for exactly 15 seconds and then complete silence for the rest of the track. Strangely enough, the waveform, which was rendered for the whole track, was still progressing fine under the playhead. A quick re-encoding using libFLAC 1.4.2 yielded the same result. Silence after 15 seconds. I resorted to having this one file in wav format. So yeah, I also think the flac decoder in Engine OS is flawed.

15

Where there’s one, plenty more are lurking.

That’s why I thought I’d report it here. A moderator should decide whether it makes sense to pass this on or if we should perhaps open a ticket.

To be honest, I don’t consider this a minor issue at all.

17

Tagged staff to be sure, but I think it’s also on the list already.