avidemux newbie: mp4 in; avi out has no video; mp4 out has washed out video

[nonexistent_entity]

I've got several mp4 videos that I want to join into one output video. All the mp4s have the same characteristics except for duration.
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For one of the MP4 files, MediaInfo sez:

Video
ID : 2
Format : AVC
Format/Info : Advanced Video Codec
Format profile : Baseline@L2.1
Format settings, CABAC : No
Format settings, ReFrames : 1 frame
Codec ID : avc1
Codec ID/Info : Advanced Video Coding
Duration : 10mn 33s
Bit rate mode : Variable
Bit rate : 501 Kbps
Maximum bit rate : 1 171 Kbps
Width : 480 pixels
Height : 360 pixels
Display aspect ratio : 4:3
Frame rate mode : Constant
Frame rate : 25.000 fps
Resolution : 8 bits
Colorimetry : 4:2:0
Scan type : Progressive
Bits/(Pixel*Frame) : 0.116

Audio
ID : 1
Format : AAC
Format/Info : Advanced Audio Codec
Format version : Version 4
Format profile : LC
Format settings, SBR : No
Codec ID : 40
Duration : 10mn 33s
Bit rate mode : Variable
Bit rate : 118 Kbps
Maximum bit rate : 160 Kbps
Channel(s) : 2 channels
Channel positions : Front: L R
Sampling rate : 44.1 KHz
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I wanted to do things as simply as possible because I'm new to video editing, so I just used "Copy" for both audio and video input and first "avi" and then "mp4" for the output format.

I opened the first file and appended all the others to it. Every time, I got the pop-up that said "H.264 detected" and talked about B frames. I said no every time. Avidemux never crashed on me.

I read something about audio going out of sync if it's VBR, so I selected "Build VBR Time Map" from the Audio drop down after I had all the inputs joined together in avidemux.

Everything's great inside avidemux. I've looked at the input and output side by side throughout the joined result. I wish I could get an output that was OK, but after 2 different failures, I decided to come here for help.

My AVI output file has no video in Winamp, DivX Pro Player or Windows Media Player.

My MP4 output file has very high video values (everything's washed out and nearly white) where the second and subsequent MP4 input files are, but where the first input file is, the video's OK. The audio and video seem to be in sync throughout the MP4 output file.

Is there some easy way to get a trouble-free output file? TIA.

[redwudz]

You might try joining them with tsMuxeR GUI, then play back with MPC-HC. I'm not sure those other players can handle AVC/AAC properly.