[MEncoder-users] Audio Sync issues

[Bill Crockett]

On 18/09/2011 11:53 PM, Jeff Cranmer wrote:

> It now plays on the little Sylvania unit, but the video is a 
> littlejumpy, even when I lower the video bitrate to 3000. I'm also 
> trying to
> encode the audio in ac3 instead of pcm, to see if that improves the
> jumpiness.  The command below is my latest attempt at this, but I'm
> getting empty audio.
>
> ## Convert to DIVX with ac3 audio encoding
> mencoder tempvid.avi -o outfile.avi -ffourcc XVID -vf harddup -ovc lavc
> -oac lavc -af lavcac3enc=0:48 -channels 2 -lavcopts
> vcodec=mpeg4:acodec=ac3_fixed:threads=8:vbitrate=4000:cmp=2:subcmp=2:trell=yes:v4mv=yes:mbd=2:aspect=16/9 -noskip -mc 0
>
> The output below suggests that I need to define the channel layout.  Can
> anyone tell me what I'm missing?
>
> MEncoder dev-SVN-r33321-4.5-openSUSE Linux 11.3 (x86_64)-Packman (C)
> 2000-2011 MPlayer Team
> success: format: 0  data: 0x0 - 0xe8ace8c
> AVI file format detected.
> [aviheader] Video stream found, -vid 0
> [aviheader] Audio stream found, -aid 1
> VIDEO:  [h264]  720x480  24bpp  23.976 fps  912.5 kbps (111.4 kbyte/s)
> [V] filefmt:3  fourcc:0x34363268  size:720x480  fps:23.976
> ftime:=0.0417
> ==========================================================================
> Opening audio decoder: [ffmpeg] FFmpeg/libavcodec audio decoders
> AUDIO: 48000 Hz, 2 ch, s16le, 128.0 kbit/8.33% (ratio: 15997->192000)
> Selected audio codec: [ffaac] afm: ffmpeg (FFmpeg AAC (MPEG-2/MPEG-4
> Audio))
> ==========================================================================
> Opening video filter: [expand osd=1]
> Expand: -1 x -1, -1 ; -1, osd: 1, aspect: 0.000000, round: 1
> Opening video filter: [harddup]
> ==========================================================================
> Opening video decoder: [ffmpeg] FFmpeg's libavcodec codec family
> Selected video codec: [ffh264] vfm: ffmpeg (FFmpeg H.264)
> ==========================================================================
> Forcing output FourCC to 44495658 [XVID].
> [ac3_fixed @ 0xb8a480]No channel layout specified. The encoder will
> guess the layout, but it might be incorrect.
> Unsupported PixelFormat 61
> Unsupported PixelFormat 53
> Pos:   0.0s      2f ( 0%)  0.00fps Trem:   0min   0mb  A-V:0.000 [0:0]
> Movie-Aspect is 1.78:1 - prescaling to correct movie aspect.
> videocodec: libavcodec (720x480 fourcc=44495658 [XVID])
> [VE_LAVC] High quality encoding selected (non-realtime)!
> Writing header...
> ODML: vprp aspect is 16:9.
> Setting audio delay to 0.096s.
> Writing header...
> ODML: vprp aspect is 16:9.
> Setting audio delay to 0.096s.
>
> Thanks
>
> Jeff
>
>
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>
I would cut "-af lavcac3enc=0:48 -channels 2" and put in "-oac lavc 
-lavcopts acodec=ac3"

BTW Rolf, where is YAMF and is it related to YAMB?

Bill