problem joining videos

[goatvideo]

Hello, i'm trying to join 2 video streams into 1 video while using mkvmerge GUI v2.9.5,

i read somewhere that both videos need to be the same image size and bitrate...
i managed to make them the same size, but i'm clueless on how to equal their bitrate,
probably i'm missing something else too, so ill leave you with the file's info

this is the error message i get when trying to "start muxing":
"Appending a track from a file to another track from the same file is not allowed. This is the case for tracks number 4 and 5"

i'm getting quite familiar with mkvtoolnix and avidemux,
so if we could keep it down to those 2 programs it would be great

Anyway here are the specs, lemme know if you need more info

Video#1:
Video:
Codec 4CC: H264
Image Size: 1280x544
Aspect Ratio: 1:1 (1:1)
Frame Rate: 23.976 fps
Frame Count: 1036 frames
Total Duration: 00:00:43.209
Audio:
Codec: DTS
Channels: Stereo
Bitrate: 16000 Bps / 128 kbps
Variable Bitrate: No
Frequency: 48000 Hz
Total Duratio: 00:04:15.083
File Size: 3.89 MB

Video#2:
Video:
Codec 4CC: AVC1
Image Size: 1280x544
Aspect Ratio: 1:1 (1:1)
Frame Rate: 23.976 fps
Frame Count: 362156 frames
Total Duration: 04:11:44.938
Audio:
Codec: AC3
Channels: 6
Bitrate: 56000 Bps / 448 kbps
Variable Bitrate: No
Frequency: 48000 Hz
Total Duratio: 04:11:44.448
File Size: 806.66 MB

Thanks a lot!

[Baldrick]

I don't think you can join the dts audio with ac3 audio...

Or do you want to make ONE mkv with 2 video tracks and 2 audio tracks?

[goatvideo]

I don't think you can join the dts audio with ac3 audio...

Or do you want to make ONE mkv with 2 video tracks and 2 audio tracks?

i need ONE mkv, with those 2 video tracks joined,
but the audio of a third file (which has the lenght or duration of those 2 files combined)

--------------------------------------

what im trying to accomplish is to replace the intro of a movie,

Video#2 is the Original Source without the Intro
Video#1 is the New intro, taken from a different Source

I want to join those 2 videos only, with the audio of the Original Source uncut

So, i think i have no problem with the audio, just joining the two video streams with different bitrate or data