mp3 "padding" problem

[TarcDnB]

Hi!

I use Subtitle Edit and Subtitle Workshop to create and time .srt files.
Lately, I've used 3 mp3 files and all produced the same problem:

- when I open the file in any player (WMP, MPC-HC, VLC), the audio starts instantly
- when I load it in the above two subtitle software, there is a ~second of silence before the audio starts.

One can generate an audio waveform in Subtitle Edit and Subtitle Workshop, and the waveform gets aligned to the very left, meaning that the waveform visually starts sooner for parts of speech than the audio...

I've made the subtitles for all 3 files, timed everything to what I hear, as I couldn't rely on the waveform (I thought it was a bug). I only checked it in external players after the work, which is how I realized there is a huge 1s delay of the .srt

I've tried looking in forums and all I found was that mp3s have some paddig/silence that most media players automatically remove.
Question: how can I ensure that if someone expects an .srt from me, it will always work and gets perfectly timed? Is it related to the .mp3 format?

Thanks!
Gabor

[sneaker]

While MP3 and other lossy codecs do have some encoder delay it is typically much shorter than 1 second. For example the default delay of LAME is 576 samples i.e. at 48 kHz it's only 0.012 seconds. So I think the issue you have been reading about is not the culprit. Maybe you have some wonky DirectShow filter that's being used by Subtitle Edit and Subtitle Workshop. Try to load an mp3 file into GraphStudioNext to see what filters it uses (and de-install it unless there is a reason to have it). To avoid such problems I recommend setting SubtitleEdit to use mpv instead of DirectShow ("video player" settings).

Just to make sure: these are simple, audio-only mp3 files - not anything with video?

[TarcDnB]

Hi, thanks so much for the quick answer!

It's great to know that I was on the wrong path altogether.

Here is what GraphStudioNext shows: https://drive.google.com/open?id=1Bc91BvDPQvGIj40VsRYRnqXBc5v99OWE

In SubtitleEdit, I tried mpv as suggested. Emptied the waveform folder in Options, loaded the video, generated the waveform, and the visual delay is still there, to the same extent.

I have already tried DirectShow, VLC, MPC-HC before, except mpv. Choosing MPC-HC threw an Access Violation error. While no difference in VLC, the cursor on the timeline (waveform) was really choppy, while it was realtime with DirectShow (separate problem, I guess)

Edit: I have also already tried the "Use ffmpeg for wave extraction" checkbox on or off (deleting the folder, too, of course)

[sneaker]

Try running the mp3 file through mp3val and maybe attach the report here.

[TarcDnB]

Thanks!

"INFO: 9739 MPEG frames (MPEG 1 Layer III), +ID3v1+ID3v2, CBR
Done!"
and a green bar below, and State = "OK"

[TarcDnB]

I think I have fixed it with CodecTweakTool, it found a broken DirectShow entry, after applying the fix, all issues are resolved. Thanks for all your help!