I seem to recall having (or seeing someone else with) this issue...
0007532: 140369740131712: Playback: CJRPlaybackEngine::Play: Playing: /data1/media/hcok/VID_20200315_100727.mp4
0007532: 140369740131712: Playback: CJRPlaybackEngine::Play: Filetype: mp4; Type: 18; Can play: 1; Playback object: 0x55d666f99820
0007532: 140369740131712: Playback: CJRPlaybackEngine::StartPlayFile: Start
0007532: 140369740131712: Playback: DependencyInstaller::GetInstalledFilename: Dependency 'linux_avcodec64' (34) is missing, installing
0007533: 140369740131712: Playback: DependencyInstaller::Install: Start
0007533: 140369568077376: Reader: CLinuxINetReader::OpenRange: Start
0007533: 140369568077376: Reader: CLinuxINetReader::OpenRange: Opening URL, Position 0
0007533: 140369568077376: Reader: CLinuxINetReader::Close: Start
0007533: 140369568077376: Reader: CLinuxINetReader::Close: This 7faa44000be0, CleanClose 0
0007533: 140369568077376: Reader: CLinuxINetReader::Close: Finish (0 ms)
0007617: 140369568077376: Reader: CLinuxINetReader::OpenRange: Elapsed MS 84.0345, initial number of headers = 5, number of loops = 0
0007617: 140369568077376: Reader: CLinuxINetReader::OpenRange: Open Succeeded. Elapsed MS 84.0547, number of headers = 5, number of loops = 0
0007617: 140369568077376: Reader: CLinuxINetReader::Close: Start
0007618: 140369568077376: Reader: CLinuxINetReader::Close: This 7faa44000be0, CleanClose 5
0007618: 140369568077376: Reader: CLinuxINetReader::Close: Finish (0 ms)
0007645: 140369568077376: Reader: CLinuxINetReader::OpenRange: Elapsed MS 26.6856, initial number of headers = 0, number of loops = 0
0007645: 140369568077376: Reader: CLinuxINetReader::OpenRange: Open Succeeded. Elapsed MS 26.7034, number of headers = 0, number of loops = 0
0007645: 140369568077376: Reader: CLinuxINetReader::OpenRange: CURL open returned error value = 77
0007645: 140369568077376: Reader: CLinuxINetReader::OpenRange: Finish (111 ms)
...
0007653: 140369740131712: Playback: DependencyInstaller::Install: Downloading package failed
0007653: 140369740131712: Playback: DependencyInstaller::Install: Finish (120 ms)
0007653: 140369740131712: Playback: DependencyInstaller::GetInstalledFilename: Failed installing dependency 34
...
0007658: 140369740131712: Playback: CJRVideoPlayerWindow::OpenFile: Filename: /data1/media/hcok/VID_20200315_100727.mp4 type: mp4. CJRVideoPlayerWindow 0x55d666fa8560
0007663: 140369740131712: Playback: CJRVideoEngine::Open: Start
0007663: 140369740131712: Playback: CJRVideoEngine::Open: FFmpeg DLLs are not available.
0007663: 140369740131712: Playback: CJRVideoEngine::Open: Finish (0 ms)
0007663: 140369740131712: Playback: CJRVideoPlayerWindow::OpenFile: Failed to open JR Video Player
I know ffmpeg is installed and ffplay works fine on the video. Another Fedora install also works fine so I must have deleted something I shouldn't have. Reinstalling the ffmpeg packages doesn't help.
Thoughts?