Why does the color rendering in video files differ before and after compression?

Question

Video

Filmed with Canon EOS 700D .
( AVC codec, MOV container ).
Then I clamped it with StaxRip (in MP4).
The picture has become more contrast and darker:

Why?
Detailed MediaInfo:

Canon

General
Format : MPEG-4
Format profile : QuickTime
Codec ID : qt 2007.09 (qt /CAEP)
File size : 1.87 GiB
Duration : 6 min
Overall bit rate : 44.4 Mb/s
com.apple.quicktime.make : Canon
com.apple.quicktime.model : Canon EOS 700D
Video
ID : 1
Format : AVC
Format/Info : Advanced Video Codec
Format profile : [email protected]
Format settings, CABAC : No
Format settings, ReFrames : 1 frame
Format settings, GOP : M=1, N=12
Codec ID : avc1
Codec ID/Info : Advanced Video Coding
Duration : 6 min
Bit rate : 42.8 Mb/s
Width : 1 920 pixels
Height : 1 080 pixels
Original height : 1 088 pixels
Display aspect ratio : 16:9
Original display aspect rat : 16:9
Frame rate mode : Constant
Frame rate : 25.000 FPS
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Progressive
Bits/(Pixel*Frame) : 0.827
Stream size : 1.80 GiB (97%)
Color range : Full
Color primaries : BT.709
Transfer characteristics : BT.709
Matrix coefficients : BT.709

StaxRip

General
Format : MPEG-4
Format profile : Base Media
Codec ID : isom (isom/avc1)
File size : 17.6 MiB
Duration : 29 s 800 ms
Overall bit rate : 4 953 kb/s
Video
ID : 1
Format : AVC
Format/Info : Advanced Video Codec
Format profile : [email protected]
Format settings, CABAC : No
Format settings, ReFrames : 3 frames
Codec ID : avc1
Codec ID/Info : Advanced Video Coding
Duration : 29 s 800 ms
Bit rate : 5 031 kb/s
Maximum bit rate : 7 779 kb/s
Width : 1 920 pixels
Height : 1 080 pixels
Display aspect ratio : 16:9
Frame rate mode : Constant
Frame rate : 25.000 FPS
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Progressive
Bits/(Pixel*Frame) : 0.097
Stream size : 17.6 MiB (100%)
Writing library : x264 core 148 r2721 72d53ab
Encoding settings : cabac=0 / ref=3 / deblock=1:0:0 / analyse=0x1:0x111 / me=hex / subme=7 / psy=1 / psy_rd=1.00:0.00 / mixed_ref=1 / me_range=16 / chroma_me=1 / trellis=1 / 8x8dct=0 / cqm=0 / deadzone=21,11 / fast_pskip=1 / chroma_qp_offset=-2 / threads=12 / lookahead_threads=2 / sliced_threads=0 / nr=0 / decimate=1 / interlaced=0 / bluray_compat=0 / constrained_intra=0 / bframes=0 / weightp=0 / keyint=250 / keyint_min=25 / scenecut=40 / intra_refresh=0 / rc_lookahead=40 / rc=abr / mbtree=1 / bitrate=5031 / ratetol=1.0 / qcomp=0.60 / qpmin=0 / qpmax=69 / qpstep=4 / ip_ratio=1.40 / aq=1:1.00

------------------
UPD
On the advice of SyavaSyava I tried XviD4PSP . The result hasn't changed. The image still becomes slightly more contrasty and darker.
That is, it's clearly not the prog, and probably not even the codecs. Is it possible that some color profiles are embedded in the original video? I don't know if video files support something like that.

Answer 1

This is a video compressor. It COMPRESSES the image, and does so lossy. In your case, semitones are lost.
AAC is a compressor for sound, if anything.