WinFF not seeing FLV audio

[ZeroGravity]

I have an FLV video which was recorded from a video webcast using comf5.com. The audio is muted for the first 12 minutes of the video. It plays in FLV players without any problem but when I bring it into WinFF to convert it to MP4, WinFF says there is no audio (anyVideo Converter gives the same error). I have another video, recorded the same way that is not muted at the start and WinFF did a beautiful job converting it.

On a hunch I got my friend to record a video muting the sound for about 30 seconds to see if that was the issue. WinFF converted this without any problems. Is it possible that WinFF searches for the audio and it found it after looking forward for 30 seconds but it "times-out" when the audio starts 12 minutes into the video.

If there are any technical details that would help please let me know. I am a web programmer doing a favor for a friend so don't know exactly where to start trouble shooting.

[bat999]

If there are any technical details that would help please let me know.

Use MediaInfo on the flv file and post the output here please.

[ZeroGravity]

Is this the output you were looking for?

General
Complete name : LIVE_Webcast_of_Let_Our_Children_GO_Part_2_462011. flv
Format : Flash Video
File size : 302 MiB
Duration : 2h 49mn
Overall bit rate : 250 Kbps

Video
Format : H.263
Codec ID : 2
Codec ID/Hint : Sorenson
Duration : 2h 37mn
Width : 320 pixels
Height : 240 pixels
Display aspect ratio : 4:3
Frame rate mode : Variable
Bit depth : 8 bits
Compression mode : Lossy

Audio
Format : Nellymoser
Codec ID : 6
Duration : 2h 49mn
Channel(s) : 1 channel
Sampling rate : 11.025 KHz
Bit depth : 16 bits

[bat999]

Is this the output you were looking for?

Yes.

The output shows the video track is Duration 2h 37mn and the audio track is Duration 2h 49mn.

Strange.

Maybe somebody else will suggest something.

[Baldrick]

Extract the audio with flvextract. Add silence to the audio so it matches the video with audacity. Mux it to new video mp4 with mymp4boxgui.

[ZeroGravity]

Thanks for the quick answers and help guys. I was surprised at the durations. I expected them to be the other way round?!?!

I tried flvextract but got an error "Unable to extract audio (Nellymoser unsupported)." Do you have any other suggestions on what I could use to extract the audio?

[bat999]

I was surprised at the durations. I expected them to be the other way round?!?!

Me too!

I tried flvextract but got an error "Unable to extract audio (Nellymoser unsupported)." Do you have any other suggestions on what I could use to extract the audio?

Hi
You probably can't extract nellymoser from the flv file.
But you can try WinFF.
Convert To...
Audio
Device Preset...
Wav for CD

This will give you a HUGE wav file (over 1.5GB for 2hr 49min).
But it should then import easily into Audacity.

[poisondeathray]

You probably can't extract nellymoser from the flv file.
But you can try WinFF.
Convert To...
Audio
Device Preset...
Wav for CD

This will give you a HUGE wav file (over 1.5GB for 2hr 49min).
But it should then import easily into Audacity.

Didn't he already try winff ?

but when I bring it into WinFF to convert it to MP4, WinFF says there is no audio (anyVideo Converter gives the same error).

It plays in FLV players without any problem

ZeroG - are you saying flv players play the audio normally from the beginning ? (no audio missing) . Which players?

[DarrellS]

You can try ffmpeg...

ffmpeg.exe -i xxx.flv xxx.wav

[poisondeathray]

well both winff and any video converter are based on ffmpeg, so he will probably get the same error message

If he was using a directshow player, it doesn't route through ffmpeg; and if that plays the flv correctly , then he could probably use directshowsource() in avisynth to encode

[ZeroGravity]

ZeroG - are you saying flv players play the audio normally from the beginning ? (no audio missing) . Which players?

It played in Adobe Media Player and Any FLV Player. The audio was muted at the begining but when I skipped forward 12 minutes to where the audio starts it played without any problems.

I will have a look at avisynth and see what happens.

[ZeroGravity]

I will have a look at avisynth and see what happens.

Ok, I downloaded and installed avisynth 2.58 (Windows 7). As you can image, being a novice, confusion bells and lights went off almost immediately. Is there a resource somewhere that can guide me through what I need to do, or can someone make some suggestions?

Is it possible for avisynth to convert the video directly to MP4 without having to demux and remux the audio?

Thanks

[ZeroGravity]

Does anyone have any thoughts or advice. I don't know if this is the right terminology but, is it possible to edit the meta data and set the length of the audio to the correct duration? The video is actually 2:37 long as indicated in the MediaInfo output above. The audio is muted for 12 minutes so why it shows it as being 12 minutes longer has me completely baffled.

I followed the directions given at the bottom of this post, https://forum.videohelp.com/threads/309615-How-to-extract-audio-nellymoser-codec, without any luck.

Any advice, no matter how left field it may seem, would be appreciated.