It's likely the frame rate is the issue. 23.976 fps.
You have only posted the bare bones of the info. The full view is found in file View - Tree. This has the option to export the full data as a text file. This can be posted in a post as straight forward text.
The Humax boxes are designed to work with UK 50Hz refresh 25fps for HD channels Video compression H264 AVC and Audio Dolby Digital (ac3). SD 25 fps Video Compression mpeg2 and audio mpeg1 layer 2.
The best way to play back files like yours is use a 4K Firestick. Install Plex on it. Install Plex on say a laptop and plug in a USB drive with your files on it. Set up plex to serve your files on the usb drive. Use plex on the firestick to play back the files.
Plex can switch the TV to playback at the correct framerate (23.976 in your example).
https://www.aftvnews.com/explanation-of-the-new-frame-rate-matching-feature-on-the-amazon-fire-tv/
You might want to experiment using free AVIdemux to remux a few to either .MKV or .MP4 containers.
http://avidemux.sourceforge.net/
Example of the data you should post
General
Complete name : D:/23.976 Example.txt
Format : MPEG-4
Format profile : Base Media
Codec ID : isom (isom/iso2/avc1/mp41)
File size : 2.05 GiB
Duration : 2 h 3 min
Overall bit rate : 2 372 kb/s
Writing application : Lavf57.71.100
Video
ID : 1
Format : AVC
Format/Info : Advanced Video Codec
Format profile : High@L4
Format settings, CABAC : Yes
Format settings, RefFrames : 4 frames
Codec ID : avc1
Codec ID/Info : Advanced Video Coding
Duration : 2 h 3 min
Bit rate : 2 200 kb/s
Width : 1 920 pixels
Height : 800 pixels
Display aspect ratio : 2.40:1
Frame rate mode : Variable
Frame rate : 23.976 (24000/1001) FPS
Minimum frame rate : 23.564 FPS
Maximum frame rate : 24.390 FPS
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Progressive
Bits/(Pixel*Frame) : 0.060
Stream size : 1.88 GiB (92%)
Writing library : x264 core 142 r2479 dd79a61
Encoding settings : cabac=1 / ref=3 / deblock=1:0:0 / analyse=0x3:0x113 / me=hex / subme=7 / psy=1 / psy_rd=1.00:0.00 / mixed_ref=1 / me_range=16 / chroma_me=1 / trellis=1 / 8x8dct=1 / cqm=0 / deadzone=21,11 / fast_pskip=1 / chroma_qp_offset=-2 / threads=18 / lookahead_threads=3 / sliced_threads=0 / nr=0 / decimate=1 / interlaced=0 / bluray_compat=0 / constrained_intra=0 / bframes=3 / b_pyramid=2 / b_adapt=1 / b_bias=0 / direct=1 / weightb=1 / open_gop=0 / weightp=2 / keyint=240 / keyint_min=24 / scenecut=40 / intra_refresh=0 / rc_lookahead=40 / rc=abr / mbtree=1 / bitrate=2200 / ratetol=1.0 / qcomp=0.60 / qpmin=0 / qpmax=69 / qpstep=4 / vbv_maxrate=25000 / vbv_bufsize=31250 / nal_hrd=none / filler=0 / ip_ratio=1.40 / aq=1:1.00
Color range : Limited
Color primaries : BT.709
Transfer characteristics : BT.709
Matrix coefficients : BT.709
Audio
ID : 2
Format : AAC
Format/Info : Advanced Audio Codec
Format profile : LC
Codec ID : 40
Duration : 2 h 3 min
Bit rate mode : Constant
Bit rate : 192 kb/s
Channel(s) : 2 channels
Channel(s)_Original : 6 channels
Channel positions : Front: L C R, Side: L R, LFE
Sampling rate : 48.0 kHz
Frame rate : 46.875 FPS (1024 SPF)
Compression mode : Lossy
Stream size : 171 MiB (8%)
Default : Yes
Alternate group : 1
| Tue 14 Jul 2020 8:44:54
#6 |