Command executed:
mencoder -v XMen3.vob -ovc copy -oac copy -of lavf -lavfopts i_certify_that_my_video_stream_does_not_use_b_frames -o XMen3.mp4
Command output:
==> Found subtitle: 1
==> Found subtitle: 2
==> Found subtitle: 3
==> Found subtitle: 4
==> Found subtitle: 5
==> Found subtitle: 6
==> Found subtitle: 7
==> Found audio stream: 128
==> Found audio stream: 137
==> Found audio stream: 130
==> Found audio stream: 131
==> Found audio stream: 132
==> Found audio stream: 133
MPEG-PS file format detected.
Searching for sequence header... OK!
VIDEO:  MPEG2  720x480  (aspect 3)  29.970 fps  9800.0 kbps (1225.0 kbyte/s)
[V] filefmt:2  fourcc:0x10000002  size:720x480  fps:29.97  ftime:=0.0334
==========================================================================
Opening audio decoder: [liba52] AC3 decoding with liba52
dec_audio: Allocating 3840 bytes for input buffer.
dec_audio: Allocating 6144 + 65536 = 71680 bytes for output buffer.
Using SSE optimized IMDCT transform
AC3: 5.1 (3f+2r+lfe)  48000 Hz  448.0 kbit/s
A52 flags before a52_frame: 0x2A
A52 flags after a52_frame: 0xA
Using MMX optimized resampler
AUDIO: 48000 Hz, 2 ch, s16le, 448.0 kbit/29.17% (ratio: 56000->192000)
Selected audio codec: [a52] afm: liba52 (AC3-liba52)
==========================================================================
[file] File size is 0 bytes
STREAM: [file] XMen3.mp4
STREAM: Description: File
STREAM: Author: Albeu
STREAM: Comment: based on the code from ??? (probably Arpi)
** MUXER_LAVF *****************************************************************
You have certified that your video stream does not contain B frames.
REMEMBER: MEncoder's libavformat muxing is presently broken and will generate
INCORRECT files in the presence of B frames. Moreover, due to bugs MPlayer
will play these INCORRECT files as if nothing were wrong!
*******************************************************************************
OK, exit
ALLOCATED STREAM N. 1, type=0
videocodec: framecopy (720x480 24bpp fourcc=10000002)
ALLOCATED STREAM N. 2, type=1
Building audio filter chain for 48000Hz/2ch/s16le -> 0Hz/0ch/??...
[libaf] Adding filter dummy 
[dummy] Was reinitialized: 48000Hz/2ch/s16le
[libaf] Adding filter format 
[format] Changing sample format from little-endian 16-bit signed int to big-endian 8-bit signed int
[dummy] Was reinitialized: 48000Hz/2ch/s16le
[format] Changing sample format from little-endian 16-bit signed int to big-endian 8-bit signed int
audiocodec: framecopy (format=2000 chans=2 rate=48000 bits=16 B/s=56000 sample-1)
Muxer frame buffer sending 2 frame(s) to the muxer.
VIDEO CODEC ID: 2
AUDIO CODEC ID: 15004, TAG: 0
MUXER_LAVF(audio stream) frame_size: 0, scale: 1, sps: 48000, rate: 56000, ctx->block_align = stream->wf->nBlockAlign; 0=1 stream->wf->nAvgBytesPerSec:56000
Writing header...
[mp4 @ 0x99d300]track 1: codec frame size is not set
Floating point exception (core dumped)