dashcam video - it is really mp4?

[Davidk]

Hi ken,
Loaded the converted file into X10, got the same result. Sound audible as imported. Selected sound mixer, waited for something to happen re the waveform; several minutes, nothing. BUT after I'd finished adding the NMEA detail to this post, re-checked the X10 display and 4 -5 mins after opening the sound mixer on that clip, there's a waveform showing there.

Noting that the sound is just a straight line - no wiggles etc in it that are usual for a sound waveform.

Also, using wikipedia, found this re that filetype NMEA:
The National Marine Electronics Association (NMEA) is a US-based marine electronics trade organization setting standards of communication between marine electronics.[1]
and that 1 superscript describes marine electronics as equipment that is resistant to, or actually waterproof. Which does describe a requirement for vehicle electronics . . .

[weaver]

Try to add to the soundtrack a Normalisation filter. In most of cases it will adjust the sound volume to the optimal level and you should see something on the soundtrack.

[Davidk]

Tried that, using 2018 and X10, same response in both versions. The only way to get the audio filters item up was to split the audio out, OK. Using the transcoded file with mp3 audio, select the split audio track, then applied the normalize filter, but the moment I tried to play the audio clip with the filter applied, VS stalled completely - mouse arrow would move around but no VS functionality responded. Only way to close it was to use Task Manager, which also said app was waiting on a user response - odd since the user could get no response at all from any mouse function selection. Happened twice with 2018, once with x10.

[weaver]

In this case probably the only thing what you can do to record the ADPCM in analog form (analog output from your PC or any device where you can play the dashcam video with sound) and add to the video as a new sound track. It can happen that the 32 kHz ADPCM has not enough data to convert it into an usable MP3 data stream.

[Davidk]

It had enough data for Handbrake to successfully convert the video audio component to an mp3, and the resulting combo clip (before applying any filters) plays Ok as long as you don't try to change the volume level.

I have wondered if those audio filters are only good for wav files, of the sort produced by the voice capture function. So I tried it out with a known good commentary file - normalize it, works fine. Repeated that with an mp3 (actually a music file but in the voice track, to approximate the test I did with the split audio) normalized it, and that worked fine to. So, it looks like whatever it is, is a feature of the normalize filter applied to the audio of the transcoded file. Curious. But it had a dramatic result - killing VS stone motherless dead as soon as the play button for the filtered file was clicked.

[weaver]

Such normalisation function is available in each audio processing program, like audiocity etc. You can try it there and probably you can close out the problem.

[asik1]

David, how come it's been 4 days and you still didn't give us 30sec clip to bite?

[Davidk]

Asik,
It began as a curiouser and curiouser thing, but turned up interesting facets. As to a file - the original is 433Mb for 3 mins - an HD file, alright. But trimming that to 30sec is probably going to modify whatever is causing the volume and filter crash.

However, this link is to a onedrive public folder with 2 files in it for you to play with
https://onedrive.live.com/?id=F258AB298 ... 2984C226A1
both 30sec long: one is just the original, and the 2nd is the transcoded file (with audio as an mp3) \
and I've just realised that trimming them using VS has also changed the frame rate from 29.97 (the original) to 25.

Have fun

[asik1]

David, those two have no sound.
MediaInfo report PCM on both but no radio....

[lata]

Hi David
Like Asik, the clips have no sound level, although the properties show as having stereo.
Its as though the recordings were done with the mic disconnected or the mic level reduced to zero?

[Ken Berry]

FWIW David, I too cannot pick up any sound either by upping the volume within the clip or turning my sound system up to full volume. As the others have already said, the Properties show the audio as stock standard LPCM. But there's just nothing there. I also tried the Original clip in both Cyberlink PowerDirector 16 and Vegas Movie Studio Platinum 15 and got the same results: nada. Movie Studio has a slight advantage in immediately showing the audio as well as the video in separate tracks. But this one shows dead flat.

I did enjoy driving along the Brisbane River, though! My hometown...

[Davidk]

Both the original files have audio, audible in VLC even if not in VS, even the transcoded one, but they are well over 3 mins long and nearly 500Mb each. It does appear that simply rendering a 30sec clip from them but at 25fps removes the audio from the original 30fps clip, when played in VLC. VS still has no audio on either clip. Not that the audio is anything to write home about - engine noise plus bumps going over bridge expansion joints. And from the various properties options - in project form or in share - there appears to be no way to open that original clip or render the trimmed clip at the original properties, ie 30fps. I've never encountered or heard of a render doing this.

The preferences question box is ticked, but regardless of the project mode (DVD or HD) it isn't asked when I import those HD files even as the only item in the timeline. Is there another way to open a clip with properties as in the clip, rather than the template project property of the vsp?

[asik1]

David, just set the dashcam to shorter clips or.....
Use XMedia Recode as I recomended gezilyon times and set it as COPY streams and get those 30sec. maybe it will do.

[lata]

Hi
sorry David but i had assumed when you said "original" that you meant just that a clip direct from the camera without and additional changes or rendering.

Can you upload an original clip, then we can try rendering to see what happens to the audio?

[Davidk]

Trevor,
I've scanned thru the dashcam memory to find a file that's reasonably small so I don't have to convert it etc, and I found one: FILE181213-071732.MP4. It's about 49sec long, and both it and it's related .nmea file (in case someone knows a bit about what they are) are also here
https://onedrive.live.com/?id=F258AB298 ... 2984C226A1
In VS, no sound, audio properties blank.
In VLC, plays fine with sound.