Seeing a strange issue when transcoding from h.264 files to h.265 files using ffmpeg and the nvidia encoder, whilst the output looks files and plays fine, if you pause the video at any point (I'm using VLC for play back) for a few seconds and resume playback, the video freezes entirely, and even seeking to a new position does not unfreeze it (audio continues to play) - if you seek normally without having paused it then the video loads instantly. You have to stop playback of the file entirely and play it again for the video to come back. The h.264 file before transcoding does not have this issue, only the output h.265 file. The command I am using is: ffmpeg -hwaccel cuda -hwaccel_output_format cuda -i "<input>" -filter:v fps=25 -c:v hevc_nvenc -b_ref_mode each -bf 4 -b_adapt 1 -preset p7 -profile:v main -tier high -tune hq -rc:v vbr -lookahead_level:v 14 -multipass:v 2 -cq:v 36 -c:a copy "<output>", I've tried with combinations of -intra-refresh 1, -single-slice-intra-refresh 1, -no-scenecut 1, -g 120, -forced-idr 1 and -force_key_frames "250" but nothing seems to fix it.

Output from running it:

ffmpeg version 9.0.1-full_build-www.gyan.dev Copyright (c) 2000-2026 the FFmpeg developers                                built with gcc 16.1.0 (Rev2, Built by MSYS2 project)                                                                    configuration: --enable-gpl --enable-version3 --enable-static --disable-w32threads --disable-autodetect --enable-cairo --enable-fontconfig --enable-iconv --enable-gnutls --enable-lcms2 --enable-libxml2 --enable-gmp --enable-bzlib --enable-lzma --enable-libsnappy --enable-zlib --enable-librist --enable-libsrt --enable-libssh --enable-libzmq --enable-avisynth --enable-libbluray --enable-libcaca --enable-libdvdnav --enable-libdvdread --enable-sdl2 --enable-libaribb24 --enable-libaribcaption --enable-libdav1d --enable-libdavs2 --enable-libopenjpeg --enable-libquirc --enable-libuavs3d --enable-libxevd --enable-libzvbi --enable-liboapv --enable-libqrencode --enable-librav1e --enable-libsvtav1 --enable-libvvenc --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxavs2 --enable-libxeve --enable-libxvid --enable-libaom --enable-libjxl --enable-libsvtjpegxs --enable-libvpx --enable-mediafoundation --enable-libass --enable-frei0r --enable-libfreetype --enable-libfribidi --enable-libharfbuzz --enable-liblensfun --enable-libvidstab --enable-libvmaf --enable-libzimg --enable-amf --enable-cuda-llvm --enable-cuvid --enable-dxva2 --enable-d3d11va --enable-d3d12va --enable-ffnvcodec --enable-libvpl --enable-nvdec --enable-nvenc --enable-vaapi --enable-vulkan --enable-libplacebo --enable-opencl --enable-libcdio --enable-openal --enable-libgme --enable-libmodplug --enable-libopenmpt --enable-libopencore-amrwb --enable-libmp3lame --enable-libshine --enable-libtheora --enable-libtwolame --enable-libvo-amrwbenc --enable-libcodec2 --enable-libilbc --enable-libgsm --enable-liblc3 --enable-libopencore-amrnb --enable-libopus --enable-libspeex --enable-libvorbis --enable-ladspa --enable-libbs2b --enable-libflite --enable-libmysofa --enable-librubberband --enable-libsoxr --enable-chromaprint --enable-whisper                                                                                                   libavutil      61.  1.101 / 61.  1.101                                                                                  libavcodec     63.  1.101 / 63.  1.101                                                                                  libavformat    63.  1.101 / 63.  1.101                                                                                  libavdevice    63.  1.101 / 63.  1.101                                                                                  libavfilter    12.  1.101 / 12.  1.101                                                                                  libswscale     10.  1.101 / 10.  1.101                                                                                  libswresample   7.  1.101 /  7.  1.101                                                                                Input #0, matroska,webm, from 'D:\file.mkv':                     Metadata:                                                                                                                 encoder         : libebml v1.3.4 + libmatroska v1.4.5                                                                   creation_time   : 2017-08-05T00:18:14.000000Z                                                                         Duration: 00:28:35.96, start: 0.000000, bitrate: 3707 kb/s                                                              Stream #0:0: Video: h264 (High), yuv420p(progressive), 1280x720, SAR 1:1 DAR 16:9, 25 fps, 25 tbr, 1k tbn (default)       Metadata:                                                                                                                 BPS             : 3449048                                                                                               BPS-eng         : 3449048                                                                                               DURATION        : 00:28:35.960000000                                                                                    DURATION-eng    : 00:28:35.960000000                                                                                    NUMBER_OF_FRAMES: 42899                                                                                                 NUMBER_OF_FRAMES-eng: 42899                                                                                             NUMBER_OF_BYTES : 739803566                                                                                             NUMBER_OF_BYTES-eng: 739803566                                                                                          _STATISTICS_WRITING_APP: mkvmerge v14.0.0 ('Flow') 64bit                                                                _STATISTICS_WRITING_APP-eng: mkvmerge v14.0.0 ('Flow') 64bit                                                            _STATISTICS_WRITING_DATE_UTC: 2017-08-05 00:18:14                                                                       _STATISTICS_WRITING_DATE_UTC-eng: 2017-08-05 00:18:14                                                                   _STATISTICS_TAGS: BPS DURATION NUMBER_OF_FRAMES NUMBER_OF_BYTES                                                         _STATISTICS_TAGS-eng: BPS DURATION NUMBER_OF_FRAMES NUMBER_OF_BYTES                                                 Stream #0:1(eng): Audio: mp3 (mp3float), 48000 Hz, stereo, fltp, 128 kb/s (default)                                       Metadata:                                                                                                                 BPS             : 128000                                                                                                BPS-eng         : 128000                                                                                                DURATION        : 00:28:35.928000000                                                                                    DURATION-eng    : 00:28:35.928000000                                                                                    NUMBER_OF_FRAMES: 71497                                                                                                 NUMBER_OF_FRAMES-eng: 71497                                                                                             NUMBER_OF_BYTES : 27454848                                                                                              NUMBER_OF_BYTES-eng: 27454848                                                                                           _STATISTICS_WRITING_APP: mkvmerge v14.0.0 ('Flow') 64bit                                                                _STATISTICS_WRITING_APP-eng: mkvmerge v14.0.0 ('Flow') 64bit                                                            _STATISTICS_WRITING_DATE_UTC: 2017-08-05 00:18:14                                                                       _STATISTICS_WRITING_DATE_UTC-eng: 2017-08-05 00:18:14                                                                   _STATISTICS_TAGS: BPS DURATION NUMBER_OF_FRAMES NUMBER_OF_BYTES                                                         _STATISTICS_TAGS-eng: BPS DURATION NUMBER_OF_FRAMES NUMBER_OF_BYTES
Stream mapping:
  Stream #0:0 -> #0:0 (h264 (native) -> hevc (hevc_nvenc))
  Stream #0:1 -> #0:1 (copy)
Press [q] to stop, [?] for help
Output #0, mp4, to 'D:\output.mp4':
  Metadata:
    encoder         : Lavf63.1.101
  Stream #0:0: Video: hevc (Main) (hev1 / 0x31766568), nv12(tv, progressive), 1280x720 [SAR 1:1 DAR 16:9], q=2-31, 25 fps, 12800 tbn (default)
    Metadata:
      encoder         : Lavc63.1.101 hevc_nvenc
      BPS             : 3449048
      BPS-eng         : 3449048
      DURATION        : 00:28:35.960000000
      DURATION-eng    : 00:28:35.960000000
      NUMBER_OF_FRAMES: 42899
      NUMBER_OF_FRAMES-eng: 42899
      NUMBER_OF_BYTES : 739803566
      NUMBER_OF_BYTES-eng: 739803566
      _STATISTICS_WRITING_APP: mkvmerge v14.0.0 ('Flow') 64bit
      _STATISTICS_WRITING_APP-eng: mkvmerge v14.0.0 ('Flow') 64bit
      _STATISTICS_WRITING_DATE_UTC: 2017-08-05 00:18:14
      _STATISTICS_WRITING_DATE_UTC-eng: 2017-08-05 00:18:14
      _STATISTICS_TAGS: BPS DURATION NUMBER_OF_FRAMES NUMBER_OF_BYTES
      _STATISTICS_TAGS-eng: BPS DURATION NUMBER_OF_FRAMES NUMBER_OF_BYTES
    Side data:
      CPB properties: bitrate max/min/avg: 0/0/0 buffer size: 0 vbv_delay: N/A
  Stream #0:1(eng): Audio: mp3 (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 128 kb/s (default)
    Metadata:
      BPS             : 128000
      BPS-eng         : 128000
      DURATION        : 00:28:35.928000000
      DURATION-eng    : 00:28:35.928000000
      NUMBER_OF_FRAMES: 71497
      NUMBER_OF_FRAMES-eng: 71497
      NUMBER_OF_BYTES : 27454848
      NUMBER_OF_BYTES-eng: 27454848
      _STATISTICS_WRITING_APP: mkvmerge v14.0.0 ('Flow') 64bit
      _STATISTICS_WRITING_APP-eng: mkvmerge v14.0.0 ('Flow') 64bit
      _STATISTICS_WRITING_DATE_UTC: 2017-08-05 00:18:14
      _STATISTICS_WRITING_DATE_UTC-eng: 2017-08-05 00:18:14
      _STATISTICS_TAGS: BPS DURATION NUMBER_OF_FRAMES NUMBER_OF_BYTES
      _STATISTICS_TAGS-eng: BPS DURATION NUMBER_OF_FRAMES NUMBER_OF_BYTES

Using ffmpeg 9.0.1 on windows (with VLC 3.0.24 on windows for playback). Any idea as to why this is happening and how to fix it?

Basically what the title says is there any video editor that I can use to switch the main audio track to the language I want from a video and then convert that video to mkv or mp4?

I tried one called avidemux but the videos glitched or lagged in some parts 😪