[MEncoder-users] Mpeg duration too short

[Peter B.]

L. Lee wrote:
> It's PAL and the aspect ratio for the source is obviously wrong. 
The source is archive material, where 16:9 material was stored in 4:3.
That's quite common with older production equipment.
As it's an important rule not to alter archive material, I've left the
aspect ratio untouched to preserve what is found on the tape :)

> I didn't
> see any significant difference in duration between input and output when I
> performed this conversion.
>   
Thanks for checking it out!
I've checked your video, and: Yes, the duration is correct (=1500 frames).

Which mencoder/mplayer revision did you use for your conversion?
I'm using the version: "MEncoder SVN-r34537-4.4.5"
(which is a very recent SVN checkout)

> mencoder vx-04690_01-026s.avi -oac lavc -channels 2 -o vx-04690_01-026s.mpg
> -demuxer lavf -ovc lavc -lavcopts
> acodec=ac3:abitrate=320:vqscale=1:mbd=0:vcodec=mpeg2video:aspect=16/9:keyint
> =15:vrc_buf_size=1835:vbitrate=7000:vratetol=7000:vrc_maxrate=7500:vrc_minra
> te=5000 -mc 0.1 -vf scale=720:480 -of mpeg -mpegopts
> format=dvd:tsaf:muxrate=40000 -fps 25 -ofps 25
>   
I've used exactly your commandline and according to ffprobe my resulting
MPEG is only 59 seconds. Again, 25 frames too short :(

Here's the commands and uncut output of my transcoding:

// -------------------------------
$ mencoder client/mpeg-duration/input/vx-04690_01-026s.avi -oac lavc
-channels 2 -o 026s-169.mpg -demuxer lavf -ovc lavc -lavcopts
acodec=ac3:abitrate=320:vqscale=1:mbd=0:vcodec=mpeg2video:aspect=16/9:keyint=25:vrc_buf_size=1835:vbitrate=7000:vratetol=7000:vrc_maxrate=7500:vrc_minrate=5000
-mc 0.1 -vf scale=720:480 -of mpeg -mpegopts
format=dvd:tsaf:muxrate=40000 -fps 25 -ofps 25

Press any key to continue...
MEncoder SVN-r34537-4.4.5 (C) 2000-2012 MPlayer Team
success: format: 0  data: 0x0 - 0x10bea1d0
libavformat version 53.29.100 (internal)
libavformat file format detected.
[lavf] stream 0: video (ffv1), -vid 0
[lavf] stream 1: audio (pcm_s16le), -aid 0
VIDEO:  [FFV1]  720x576  24bpp  25.000 fps    0.0 kbps ( 0.0 kbyte/s)
[V] filefmt:35  fourcc:0x31564646  size:720x576  fps:25.000  ftime:=0.0400
Input fps will be interpreted as 25.000 instead.
==========================================================================
Opening audio decoder: [pcm] Uncompressed PCM audio decoder
AUDIO: 48000 Hz, 2 ch, s16le, 1536.0 kbit/100.00% (ratio: 192000->192000)
Selected audio codec: [pcm] afm: pcm (Uncompressed PCM)
==========================================================================
PACKET SIZE: 2048 bytes, deltascr: 11059
libavcodec version 53.54.100 (internal)
Opening video filter: [expand osd=1]
Expand: -1 x -1, -1 ; -1, osd: 1, aspect: 0.000000, round: 1
Opening video filter: [scale w=720 h=480]
==========================================================================
Opening video decoder: [ffmpeg] FFmpeg's libavcodec codec family
Selected video codec: [ffv1] vfm: ffmpeg (FFV1 (lossless codec))
==========================================================================
[ac3 @ 0x8b215c0]channel_layout not specified
[ac3 @ 0x8b215c0]No channel layout specified. The encoder will guess the
layout, but it might be incorrect.
Limiting audio preload to 0.4s.
Increasing audio density to 4.
Movie-Aspect is undefined - no prescaling applied.
[swscaler @ 0x8a9d9e0]BICUBIC scaler, from yuv422p to yuv420p using MMX2
videocodec: libavcodec (720x480 fourcc=3267706d [mpg2])
[VE_LAVC] Using constant qscale = 1.000000 (VBR).
[mpeg2video @ 0x8b215c0]Warning min_rate > 0 but min_rate != max_rate
isn't recommended!
[swscaler @ 0x8a9d9e0]Warning: dstStride is not aligned!
         ->cannot do aligned memory accesses anymore
[swscaler @ 0x8a9d9e0]Warning: data is not aligned! This can lead to a
speedloss
Writing header...
INITV: 0.200, 0.160, fps: 25.000
Pos:  60.0s   1500f (99%) 32.22fps Trem:   0min  38mb  A-V:0.044 [5061:320]

Flushing video frames.
Writing index...

Overhead: 1.642% (652169 / 39720055)
Writing header...

Video stream: 5061.373 kbit/s  (632671 B/s)  size: 37960301 bytes 
60.000 secs  1500 frames

Audio stream:  320.000 kbit/s  (40000 B/s)  size: 2400000 bytes  60.000 secs


// ------------------------
$ ffprobe 026s-169.mpg

ffprobe version N-36728-g794006f Copyright (c) 2007-2012 the FFmpeg
developers
  built on Jan 12 2012 09:16:04 with gcc 4.4.5
  configuration: --prefix=/usr/local --enable-gpl --enable-nonfree
--enable-postproc --enable-swscale --enable-avfilter --enable-pthreads
--enable-bzlib --enable-libmp3lame --enable-libvorbis --enable-libxvid
--enable-zlib --enable-libopenjpeg --enable-decoder=png
--enable-encoder=png --enable-libdirac --enable-libschroedinger
  libavutil      51. 34.100 / 51. 34.100
  libavcodec     53. 55.100 / 53. 55.100
  libavformat    53. 29.100 / 53. 29.100
  libavdevice    53.  4.100 / 53.  4.100
  libavfilter     2. 58.100 /  2. 58.100
  libswscale      2.  1.100 /  2.  1.100
  libswresample   0.  6.100 /  0.  6.100
  libpostproc    51.  2.100 / 51.  2.100
[mpeg @ 0x9dbe320] max_analyze_duration 5000000 reached at 5000000
Input #0, mpeg, from '026s-169.mpg':
  Duration: 00:00:59.00, start: 0.240000, bitrate: 5474 kb/s
    Stream #0:0[0x1e0]: Video: mpeg2video (Main), yuv420p, 720x480 [SAR
32:27 DAR 16:9], 7500 kb/s, 25 fps, 25 tbr, 90k tbn, 50 tbc
    Stream #0:1[0x80]: Audio: ac3, 48000 Hz, stereo, s16, 320 kb/s