Okay this one might be a bit hard to explain.

Was recording an MPD DASH stream using N_m3u8DL-RE and was not aware that in the first hour of the stream being live it was outputting a garbage 4x64 video stream before sending out 1080p30 video an hour later.

Everytime I try to remux the recorded mp4 and m4a file it keeps reporting itself to be 1 hour and 36 minutes long and at a bitrate of 76mbps when in actuality it is 12 hours long at a bitrate of 9mbps.

The M4A file also reports itself as being "H264" even though it's within an .m4a container.

I believe this might be caused by a corrupted header (if not the header from the different video coming in the first hour) but I'm not sure.

Here is the ffprobe for the video file.

Code:
D:\youtubedl>ffprobe "D:\OUTSIDE_LANDS_2025--CHOXUWU\DAY_1\AMAZON_PRIME_STREAM\c
enc_2025-08-08_11-35-17.mp4"
ffprobe version N-114833-g5e380bcdb1-20240415 Copyright (c) 2007-2024 the FFmpeg
 developers
  built with gcc 13.2.0 (crosstool-NG 1.26.0.65_ecc5e41)
  configuration: --prefix=/ffbuild/prefix --pkg-config-flags=--static --pkg-conf
ig=pkg-config --cross-prefix=x86_64-w64-mingw32- --arch=x86_64 --target-os=mingw
32 --enable-gpl --enable-version3 --disable-debug --disable-w32threads --enable-
pthreads --enable-iconv --enable-libxml2 --enable-zlib --enable-libfreetype --en
able-libfribidi --enable-gmp --enable-fontconfig --enable-libharfbuzz --enable-l
ibvorbis --enable-opencl --disable-libpulse --enable-libvmaf --disable-libxcb --
disable-xlib --enable-amf --enable-libaom --enable-libaribb24 --enable-avisynth
--enable-chromaprint --enable-libdav1d --enable-libdavs2 --enable-libdvdread --e
nable-libdvdnav --disable-libfdk-aac --enable-ffnvcodec --enable-cuda-llvm --ena
ble-frei0r --enable-libgme --enable-libkvazaar --enable-libaribcaption --enable-
libass --enable-libbluray --enable-libjxl --enable-libmp3lame --enable-libopus -
-enable-librist --enable-libssh --enable-libtheora --enable-libvpx --enable-libw
ebp --enable-lv2 --enable-libvpl --enable-openal --enable-libopencore-amrnb --en
able-libopencore-amrwb --enable-libopenh264 --enable-libopenjpeg --enable-libope
nmpt --enable-librav1e --enable-librubberband --enable-schannel --enable-sdl2 --
enable-libsoxr --enable-libsrt --enable-libsvtav1 --enable-libtwolame --enable-l
ibuavs3d --disable-libdrm --enable-vaapi --enable-libvidstab --enable-vulkan --e
nable-libshaderc --enable-libplacebo --enable-libx264 --enable-libx265 --enable-
libxavs2 --enable-libxvid --enable-libzimg --enable-libzvbi --extra-cflags=-DLIB
TWOLAME_STATIC --extra-cxxflags= --extra-libs=-lgomp --extra-ldflags=-pthread --
extra-ldexeflags= --cc=x86_64-w64-mingw32-gcc --cxx=x86_64-w64-mingw32-g++ --ar=
x86_64-w64-mingw32-gcc-ar --ranlib=x86_64-w64-mingw32-gcc-ranlib --nm=x86_64-w64
-mingw32-gcc-nm --extra-version=20240415
  libavutil      59. 15.100 / 59. 15.100
  libavcodec     61.  5.103 / 61.  5.103
  libavformat    61.  3.100 / 61.  3.100
  libavdevice    61.  2.100 / 61.  2.100
  libavfilter    10.  2.101 / 10.  2.101
  libswscale      8.  2.100 /  8.  2.100
  libswresample   5.  2.100 /  5.  2.100
  libpostproc    58.  2.100 / 58.  2.100
[mov,mp4,m4a,3gp,3g2,mj2 @ 00000000004daf40] could not find corresponding trex (
id 1)
[mov,mp4,m4a,3gp,3g2,mj2 @ 00000000004daf40] could not find corresponding track
id 0
[mov,mp4,m4a,3gp,3g2,mj2 @ 00000000004daf40] trun track id unknown, no tfhd was
found
[mov,mp4,m4a,3gp,3g2,mj2 @ 00000000004daf40] error reading header
D:\OUTSIDE_LANDS_2025--CHOXUWU\DAY_1\AMAZON_PRIME_STREAM\cenc_2025-08-08_11-35-1
7.mp4: Invalid data found when processing input
And here is a sample of both the corrupted video/audio files and a healthy recording from the same exact DASH stream.

Code:
https://gofile.io/d/ozJatt
Any help would be appreciated!