no sound in some mp4 files converted from wmv (Avidemux 2.7.6, Windows 10)

[mahesh]

I have already used Avidemux a few times successfully, and was therefore satisfied with it. But I am now having trouble converting some files. Possibly I am missing something.

This is my first post on the Forum, and I welcome guidance on how to be a good participant in it.

I am using Avidemux 2.7.6, Windows 10.

I would like to focus first on wmv files that I am converting to mp4. The problem is that some of the resulting mp4 files have no sound, while others are fine and do have sound.

More specifically, it seems the problem occurs only when converting wmv files that were converted from original arf recordings (of Webex). On the other hand, there seems to be no problem when converting wmv files which were originally wrf recordings – that is, in this case the resulting mp4 files are complete with sound.

My question: What is causing the problem and how to solve it?

Context info: The wmv files I am trying to convert were converted from original wrf and arf recording files of Webex meetings by using the appropriate/correspondent Webex players (each type of recording has a specific player which can play and convert the correspondent files). Since I don't have a Webex account anymore, I am not allowed to convert the Webex files directly to mp4. I am converting to mp4 only to save disk space.

Summing up my observations and the problem found:
* No problem in the conversion to mp4 of wmv files converted from wrf recordings: sound is there.
* Conversion of wmv files converted from arf recordings: no problem in the video, but no sound is there in the output mp4 files.

The procedure I am using to convert from wmv to mp4 in Avidemux is the following:
open file
change settings:
Video Output --> Mpeg4 AVC (x264)
Audio Output --> AAC (lav) [Gives error when using the default option "Copy"]
Output Format --> MP4 Muxer
save file

I have previously tried (extensively but not exhaustively) to find similar issues discussed in this Forum, but wasn't able to find any that could give me a solution to my issue.

[eumagga0x2a]

1. Please update your Avidemux build to a supported version which is at least the last release (2.7.8.) or – much better – the latest available nightly build (currently from May 11).
2. Please load the problematic WMV file in Avidemux, close Avidemux and attach the log file admlog.txt from %localappdata%\avidemux to your reply (you may need to compress it first).

What is causing the problem and how to solve it?

Avidemux log will help to assess the problem. Further steps depend on the information it will hopefully provide.

[mahesh]

Thanks a lot for your prompt reply! I'm sorry for taking so long to answer. I had set up to receive all notifications by email, but I didn't receive any email. I checked the junk email folder, but nothing is there also. And on June 13 I had problems with my computer - had to get another HDD and resintalled Windows 10.

Anyway, I followed the steps provided, so attached is the admlog.txt file after loading one of the problematic files and then closing Avidemux.

Also as recommended/instructed, I am now running Avidemux 2.7.9, which I have just installed through the file avidemux_2.7.9 r210702_win64.exe, which I downloaded from the link provided (from the win64 folder).

An information that may be relevant, and which I forgot to mention before, is that these problematic files (wmv files converted from arf files) have no sound already when playing in Avidemux. In other words, it's not just that the output mp4 files converted from them don't have sound, but when playing inside Avidemux itself the problematic files have no sound. And this contrary to when opening and playing in Avidemux wmv files converted from wrf files (the unproblematic ones), which have sound inside Avidemux, and whose converted mp4 files also have. It may also be good to clarify that the problematic wmv files do have sound in other players, like in MPC-HC.

Just let me know if more information is needed, and thank you again for your attention/help!

P.S.: If there is a way I can receive notifications by email, that would be helpful to speed up my response next time. Perhaps I am not setting up things correctly somehow? Of course I left checked the "Notify me of replies" option (just below).

[eumagga0x2a]

The problematic audio track uses Windows Media Audio 9 Lossless codec. I was able to generate a sample WMV file with such an audio track so that I could add support for this rarely used codec to Avidemux (for now just in my private builds).

I'm hesitating somewhat to push the necessary changes to the repository as this means enabling one more hardly used decoder in the bundled FFmpeg for a format which is as good as dead = growing attack surface / security concerns + increased size of the application + more bugs. In any case, it would be great if you could provide a real-life sample file via WeTransfer, Mega, Dropbox or Google Drive, given the content is innocuous enough.

If there is a way I can receive notifications by email, that would be helpful to speed up my response next time.

Honestly, I don't know. Maybe there is a bug in the SMF software or notifications end up in a spam filter. I personally never use notifications per email and proactively check the forum for new posts.

[eumagga0x2a]

This is just a reminder that the availability of a real-life sample with WMA Lossless codec is a pre-condition for adding decoding support for such audio tracks in Avidemux. If CleanTalk external antispam service prevents you from posting a link to sample, please provide it by a personal message.

[mahesh]

Thanks for explaining the issue and the situation.

Here's the link to a small sample out of one of the problematic wmv files:

https://drive.google.com/file/d/1Itu9v0MCo-fgxAoa1ENFznyiiNmOF6Qr/view?usp=sharing

Please note that I cut this sample out of the wmv file using asfbinwin1.8.2.903. It is said this application by default cuts from asf/wmv files without reencoding. So I hope it is a faithful sample of the original file. (In asfbin, I removed a couple of advanced options that were checked by default, trying to make sure the original content would not be changed or reencoded. But I am not sure this is the way to do it. Please let me know if not, and how I could obtain a sample from the large wmv files I have.) The resulting file had the extension asf, so, following advice I read on a website, I just renamed/changed the extension to wmv. It seems this worked – at least it's playing fine.

By the way, after your helpful clarification about the issue, I found that the arf player from Webex allows the arf files to be converted to wmv using one out of three different codecs – I was using Windows Media Audio 9.2 Lossless, so now I have tried Windows Media Audio 10 Professional (the 3rd option being Windows Media Audio 9.2). Now, when playing the output wmv in Avidemux, and converting it to mp4 using the same procedure as before, the sound is there!

I found this sucessful outcome curious because, looking at the Avidemux audio decoders (http://www.avidemux.org/admWiki/doku.php?id=general:audio_decoders), I didn't see any decoder which in my view resembles Windows Media Audio, what to speak of Windows Media Audio 10 Professional. So it seems to me that either the list in that link is outdated (was last modified in 2012, so would not be surprising), or I lack the understanding to see all that is implicitly listed there. Anyway, I believe some decoder for Windows Media Audio 10 Professional must be there already in/for Avidemux, right?   

Regarding notifications by email, it's working now. I think the problem was that I somehow had missed/overlooked an important checkbox: Notification Preferences --> General Settings --> checkbox "Receive forum newsletters, announcements and important notifications by email" was not checked! I have checked it and have received a notification about your last message.

[eumagga0x2a]

Thank you for the sample, I've pushed a patch which enables Avidemux to play the audio track in this file to the repository.

[eumagga0x2a]

[...] looking at the Avidemux audio decoders (https://www.avidemux.org/admWiki/doku.php?id=general:audio_decoders), I didn't see any decoder which in my view resembles Windows Media Audio, what to speak of Windows Media Audio 10 Professional. So it seems to me that either the list in that link is outdated (was last modified in 2012, so would not be surprising), or I lack the understanding to see all that is implicitly listed there. Anyway, I believe some decoder for Windows Media Audio 10 Professional must be there already in/for Avidemux, right?

The Wiki is very outdated. Starting to update it is on my todo list, but at least the entries for libmad and liba52 are still valid.

All audio and (software) video decoders enabled in the bundled FFmpeg libraries are mentioned here. Additionally, Avidemux supports decoding of the AV1 video codec via bundled libaom.