Subtitle Edit cannot load the audio from mkv

[loninappleton]

Everything looks like a standard mkv but there is some odd notation for audio in the MediInfo and I've copied it here.

Looks like an AAC low complexity what ever that means. It cannot complete but at least appears to start the demux. I know the owner of the original likes to upscale things. This is an old BBC play from 1957. Could be from DVD archives then an ISO in 2019.

General
Complete name : C:\********\Brand BBC\Brand.mp4
Format : MPEG-4
Format profile : Base Media / Version 2
Codec ID : mp42 (isom/mp42)
File size : 598 MiB
Duration : 1 h 29 min
Overall bit rate mode : Variable
Overall bit rate : 936 kb/s
Frame rate : 30.000 FPS
Encoded date : 2019-10-02 19:35:33 UTC
Tagged date : 2019-10-02 19:35:33 UTC
Writing application : Google
gsst : 0
gstd : 5368895

Video
ID : 1
Format : AVC
Format/Info : Advanced Video Codec
Format profile : High@L3.1
Format settings : CABAC / 3 Ref Frames
Format settings, CABAC : Yes
Format settings, Reference frames : 3 frames
Codec ID : avc1
Codec ID/Info : Advanced Video Coding
Duration : 1 h 29 min
Bit rate : 804 kb/s
Width : 1 280 pixels
Height : 720 pixels
Display aspect ratio : 16:9
Frame rate mode : Constant
Frame rate : 30.000 FPS
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Progressive
Bits/(Pixel*Frame) : 0.029
Stream size : 514 MiB (86%)
Title : ISO Media file produced by Google Inc. Created on: 10/02/2019.
Encoded date : 2019-10-02 19:35:33 UTC
Tagged date : 2019-10-02 19:35:33 UTC
Color range : Limited
Color primaries : BT.709
Transfer characteristics : BT.709
Matrix coefficients : BT.709
Codec configuration box : avcC

Audio
ID : 2
Format : AAC LC
Format/Info : Advanced Audio Codec Low Complexity
Codec ID : mp4a-40-2
Duration : 1 h 29 min
Bit rate mode : Variable
Bit rate : 128 kb/s
Channel(s) : 2 channels
Channel layout : L R
Sampling rate : 44.1 kHz
Frame rate : 43.066 FPS (1024 SPF)
Compression mode : Lossy
Stream size : 81.8 MiB (14%)
Title : ISO Media file produced by Google Inc. Created on: 10/02/2019.
Language : English
Encoded date : 2019-10-02 19:35:33 UTC
Tagged date : 2019-10-02 19:35:33 UTC

[abolibibelot]

Looks like it's a MP4 not MKV. Not sure what “low complexity” means but it's not uncommon, the audio seems pretty standard.
Either way you can simply demux the audio with a command like:

ffmpeg -i "Brand.mp4" -vn -c copy "Brand.m4a"

And if that still doesn't work, decompress it:

ffmpeg -i "Brand.mp4" -vn "Brand.wav"

It requires ffmpeg.exe, you probably have at least one version somewhere on your system already.
If there's some kind of corruption, there should be some kind of warning in the ffmpeg output.
Perhaps there's not enough space. I haven't updated Subtitle Edit in a long while, don't know what it does with the audio when importing a video, if it decompresses the whole stream it needs about 1GB, either on the system partition or on the partition where the source file is located.

[loninappleton]

Thanks for the reply. Yes, apologies for the mp4 mistake. On the code, I'm very poor at understanding command line. It's not a necessity on the sub I'm making but good to know there's a fix.

[cholla]

For the code: You can't use -vn & -c copy at the same time.
What you want is:

ffmpeg -i "Brand.mp4" -vn -c:a copy "Brand.m4a"

If you want only the audio. And there are no subtitles in this .mp4.
It there are subtitles & you want to remove those also add -sn to the command.

[abolibibelot]

Thanks for the reply. Yes, apologies for the mp4 mistake. On the code, I'm very poor at understanding command line. It's not a necessity on the sub I'm making but good to know there's a fix.

So... there's no issue after all?
Those commands are very basic, your grandma should be able to understand them, perhaps even your cat... “-i” means “input”, “-vn” means “no video stream in the output”, “-c copy” (or -c:a to process only the audio) means “the stream(s) will be copied with no transcoding”; when not using “-c copy” (or “-c:a copy”) if no extra parameters are specified it converts the video/audio stream(s) with the default settings, relying on the extension of the output file, in this case with the .wav extension it will convert to standard 16-bit stereo PCM in a WAV container, which is uncompressed audio.

@“cholla”

For the code: You can't use -vn & -c copy at the same time.

In my experience it does work and yield the exact same output file, I just tested extracting the audio from a MP4 with either “-c copy” or “-c:a copy”. (I'm currently using version 4.4 from 2021. I'm a big advocate of the “if it's not broken don't fix it” motto, and it still works fine for the basic tasks I need it for as of now. But I doubt that such a basic behaviour has been changed since.)

[cholla]

@ abolibibelot,
I have just always used "-c:a copy" but I will give “-c copy” a test.
The reason is I believe that "-c:a copy" is the instruction to extract the audio.
With "-c copy" if you want the subtitles from a file.
With even some -map or specific codec if this is what I want.
For ffmpeg I use the unofficial versions from this topic here at VH:
Because I'm using windows 7.
They are not numbered the same way as official versions.
They are created & posted by member autodidact.
https://forum.videohelp.com/threads/414767-ffmpeg-7-0-1-and-Windows-7/page2#post2771491

[abolibibelot]

With "-c:s copy" if you want the subtitles from a file.

There should be something in this forum's code to distinguish between intentional emotes and code falsely interpreted as an emote. When there's no space before it shouldn't be interpreted as an em:ote.

For ffmpeg I use the unofficial versions from this topic here at VH:
Because I'm using windows 7.

So the official ffmpeg stopped working on W7 too, damn, those walls are closing in...
Right now it won't bother me, but which significant features have been added or improved in the past 5 years that would warrant an update?

[cholla]

I agree on the emojies.
This works. I should have proofread.

c:s copy

One feature of the ffmpeg version I use is it has the Apple aac_at

[ProWo]

Everything looks like a standard mp4 but there is some odd notation for audio in the MediInfo and I've copied it here...

You could simply remux it and retry the remuxed one in Subtitleedit.
For the remux (fast, streamcopy, so there is no quality loss) your can use clever FFmpeg-GUI.

[loninappleton]

OP here. I have the clever ffmpeg and know that interface slightly.

On 'so there's no problem' from above, no I think the problem exists but I didn't have the ability to fix it and it's something I can work around.
But I'll load the clever ffmpeg and see if I can find remux. If it's getting the audio out as a demux, that can be done with Audacity or Goldwave, both of which I've used.

[loninappleton]

To refresh myself on things here which I had not been using for some time..

https://www.google.com/search?client=firefox-b-1-d&q=remux+an+audio+file+to+mkv

That's just a google AI response to remind me of MKVToolnix to do the remux.
For the audio I updated my Audacity and ffmpeg for Audacity (a separate procedure needed for Audacity)
then had it export as AC3... AAC as the original is not an option. So I took that into Toolnix and checked the right box to save as MKV with the new audio file. The old file will not care much about the container.
Once done I loaded my work copy of my SRT for this job into Subtitle Edit and dragged the new MKV to the vid window
then clicked on ' add the audio.'

Still nothing and I let it run 5 minutes and more

I used the tools I'm familiar with to do what was initially suggested.

What I'll do is just go grab and old project where everything was working and make a test.

[ProWo]

But I'll load the clever ffmpeg and see if I can find remux.

It's easy. Start clever, drag your mp4 onto, click multiplex.
Set mp4 as container and click multiplex.
Done.

[loninappleton]

The problem must be elsewhere since the click to get audio window is not working with multiple tries I've made with other video.

You try it. That's the best. Some baseline video/srt to work off of. I've now watched that progress bar all I can take. ;/

I'll check my install of the player, but yes, someone here actually use the current SE and yell me it works fine for them.

[loninappleton]

Screenshot shows MPV player installed.
I'm going through this as troubleshooting.