Problems with MTS (AVCHD) files - video is twice as long as it should be

Thats odd, as I see a temporal offset between the lines in each frame?

Then it sounds as if you have true 50i footage. You need to query it with a reliable method (again try MediaInfo worth it’s weight in gold if you do a lot of video).

This is what I get from MediaInfo:

General
ID : 0 (0x0)
Complete name : /media/02EE82FEEE82E96D/DOCUMENTARY/00076.MTS
Format : BDAV
Format/Info : Blu-ray Video
File size : 15.0 MiB
Duration : 7s 740ms
Overall bit rate mode : Variable
Overall bit rate : 16.2 Mbps
Maximum Overall bit rate : 18.0 Mbps

Video
ID : 4113 (0x1011)
Menu ID : 1 (0x1)
Format : AVC
Format/Info : Advanced Video Codec
Format profile : [email protected]
Format settings, CABAC : Yes
Format settings, ReFrames : 2 frames
Format settings, GOP : M=2, N=13
Codec ID : 27
Duration : 7s 720ms
Bit rate mode : Variable
Bit rate : 15.1 Mbps
Maximum bit rate : 16.0 Mbps
Width : 1 440 pixels
Height : 1 080 pixels
Display aspect ratio : 16:9
Frame rate : 25.000 fps
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Interlaced
Scan order : Top Field First
Bits/(Pixel*Frame) : 0.388
Stream size : 13.9 MiB (92%)

Audio
ID : 4352 (0x1100)
Menu ID : 1 (0x1)
Format : AC-3
Format/Info : Audio Coding 3
Mode extension : CM (complete main)
Format settings, Endianness : Big
Codec ID : 129
Duration : 7s 808ms
Bit rate mode : Constant
Bit rate : 448 Kbps
Channel(s) : 6 channels
Channel positions : Front: L C R, Side: L R, LFE
Sampling rate : 48.0 KHz
Bit depth : 16 bits
Compression mode : Lossy
Delay relative to video : -80ms
Stream size : 427 KiB (3%)

I have tried EyeFrame, but none of the option rewraps or converts the video to a format that blender (or any media player) will playback without parallel horizontal lines (and sometimes more problems).