Missing sound in output

[yetanotherlogin]

Hello

I don't know if it's due to my using the 2.6 branch (r8273) or some other cause.

The input file is this:

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Stream #0:0[0x1e0]: Video: mpeg2video (Main), yuv420p, 720x576 [SAR 64:45 DAR 16:9], 25 fps, 25 tbr, 90k tbn, 50 tbc
Stream #0:1[0x80]: Audio: ac3, 48000 Hz, 5.1(side), s16, 448 kb/s


I used a filter to brighten it a bit because it's too dark, and resized the video to 300x240.

Here's the output I chose:

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Video:Mpeg4 AVC (x264)
Audio: AAC (Faac)
Output format: MP4 Muxer


When played in VLC or Splash, the video is fine but there's no sound.

Any idea what it could be?

Thank you.

[yetanotherlogin]

If someone is willing to investigate, I uploaded a 15s sample here.

FWIW, I used the following command to extract this 15s sample:

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ffmpeg.exe -i original.mpg -ss 00:00:00 -t 00:00:15 -c:v copy -c:a copy original.sample.mpg


Thank you.

[Jan Gruuthuse]

No idea what is going or why. When you check audio tracks in VLC it shows 14 tracks. Mediainfo tells us it AC3?
You can recover audio with dropping the video on audacity.
Main question how did you get/obtain the source video (dvd)? Did you do any processing on it?
Try one of these and see if result changes.

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ffmpeg -ss 00:15:00 -i original.mpg -t 5 -c:v copy -c:a copy original.sample.mpg

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ffmpeg -ss 00:15:00 -i original.mpg -t 5 -c copy -map 0 original.sample.mpg

The used OS and used flavor of ffmpeg could come into play allso.

[yetanotherlogin]

I simply ran "copy /b *.mpg output.mpg" in Windows to combine the different MPEG files into a single file. It plays OK in VLC and Splash, so I guess the input file is kosher.

Apparently, ffmpeg is buggy, hence the multiple streams in the sample.

I downloaded the latest AviDemux 2.6 beta release (r8295), applied the two filters, and extracted a 2mn sample... which, again, has no sound in VLC.

FWIW, the settings in AviDemux were the same as the previous test: Video Output = Mpeg4 AVC (x264) + Audio Output = AAC (Faac), and Output Format = MP4 Muxer.

Would you know of a reliable Windows application I could use to extract a sample from the original file so that someone could play with it in AviDemux?

Thank you.
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Edit: The two ffmpeg commands in your post have the same issue : 15 streams, and no sound. So there's definitely something fishy in ffmpeg ("N-46469-gc995644 built on Nov  5 2012").

[Jan Gruuthuse]

What happens when you open 1st part in avidemux and append 2nd part ([Ctrl][Alt][A] avidemux 2.5, [Ctrl][A] avidemux 2.6) and save this with copy for video and audio? Not sure if that is a good idea to

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"copy /b *.mpg output.mpg" , why would we else need programs to join videos?

[yetanotherlogin]

What happens when you open 1st part in avidemux and append 2nd part ([Ctrl][Alt][A] avidemux 2.5, [Ctrl][A] avidemux 2.6) and save this with copy for video and audio?

I...
1. opened the first file in AD,
2. answered Yes when prompted whether to load all the files that are sequentially numbered,
3. applied the two filters
4. selected a 30s sample using the A and B buttons
5. File > Save

No sound in VLC, although it only has two streams (video + sound) (success! ;-)). Here's the output.

Not sure if that is a good idea to

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"copy /b *.mpg output.mpg" , why would we else need programs to join videos?

True, but I read that it was OK to do this on MPEG files. Maybe it's wrong, but the file does play OK in VLC. I'll try to find a reliable Windows application to extract a sample from any of the original MPEG files.

Thank you.

[yetanotherlogin]

Using AD 2.5.6-1 Zip (32 bits) and MPEG4-AVC + AAC (Faac) + MP4, the file has video and audio.

So it looks like AD 2.6 has a problem with the settings I used.

However, audio and video seem slightly out of sync. Here's a 30s sample.

[Jan Gruuthuse]

Can not reproduce this:
- source video missing
- details of what exactly you are doing (steps, settings for video and audio re-encoding)
- what are you trying to achieve? Source (device) video to target (device) video?
only providing an end result video is not enough.

The last sample had an audio down mix to one channel. Amongst the problems I suspect, is the channel mapping going from one audio codec to another.

[yetanotherlogin]

Thanks for the help. The video is actually fine, it was just an impression.

Those tips will in handy the next time I need to edit a video.

Thanks all.

[jimlad]

I had problems mixing 2 different file types (eg raw AVI + mpg) loosing sound etc and crashes.

What worked however was to convert each file individually to the final required format, then merge them via COPY, so that there is no loss of quality.

[styrol]

I had problems mixing 2 different file types (eg raw AVI + mpg)

Files must come from the same source (same resolution, same encoding etc.)! The MOV container is able to store more than one video and audio tracks from different source. But only QuickTime Player is able to play such files.