user30250: I am dealing with a video that as a codec tag of none, but the actual codec is GHEC.  I am aware this is a proprietary codec from GeoVision.  The video will not play unless I use ffplay with the -vcodec hevc argument.  Since GHEC codec will play via hevc codec, is there any way I can force the codec to be hevc on this video so I can watch it in other media players like VLC?
Here are the streams from ffprobe:
    Stream #0:0: Video: none (GHEC / 0x43454847), none, 1920x1080, 451 kb/s, 30 fps, 30 tbr, 30 tbn, 30 tbc
    Stream #0:1: Subtitle: none, 3 kb/s
    Stream #0:2: Subtitle: none


user39248: Just an FYI - you can't just force a codec if the moov atom or headers are missing.
For that you need to repair the file by copying valid headers and atoms from another functional file created the same way.
The only utility that worked for me was https://codecpack.co/download/recover-mp4.html - which gives instructions when run without arguments, runs fine on wine, and worked, unlike untrunc and a bunch of other ffpmeg-based utilities.

user1871: If you know the compatible codec in ffmpeg, you can remux the file to generate a standard file, e.g.
ffmpeg -c:v hevc -i in.avi -c copy out.avi


30250: <p>I am dealing with a video that as a codec tag of <code>none</code>, but the actual codec is <code>GHEC</code>.  I am aware this is a proprietary codec from GeoVision.  The video will not play unless I use ffplay with the <code>-vcodec hevc</code> argument.  Since <code>GHEC</code> codec will play via <code>hevc</code> codec, is there any way I can force the codec to be <code>hevc</code> on this video so I can watch it in other media players like VLC?</p>
<p>Here are the streams from ffprobe:</p>
<pre><code>    Stream #0:0: Video: none (GHEC / 0x43454847), none, 1920x1080, 451 kb/s, 30 fps, 30 tbr, 30 tbn, 30 tbc
    Stream #0:1: Subtitle: none, 3 kb/s
    Stream #0:2: Subtitle: none
</code></pre>
 39248: <p>Just an FYI - you can't just force a codec if the <code>moov atom</code> or <code>headers</code> are missing.</p>
<p>For that you need to repair the file by copying valid headers and atoms from another functional file created the same way.</p>
<p>The only utility that worked for me was <a href="https://codecpack.co/download/recover-mp4.html" rel="nofollow noreferrer">https://codecpack.co/download/recover-mp4.html</a> - which gives instructions when run without arguments, runs fine on <code>wine</code>, and worked, unlike <code>untrunc</code> and a bunch of other ffpmeg-based utilities.</p>
 1871: <p>If you know the compatible codec in ffmpeg, you can remux the file to generate a standard file, e.g.</p>
<pre><code>ffmpeg -c:v hevc -i in.avi -c copy out.avi
</code></pre>
