-={ 2021-06-12 23:20:41.269312845+00:00 }=-

Hey Maurice!

Here is even a better way to find out what codecs mplayer supports'

 $ mplayer -vc help

or -va for audio codecs.  For this particular discussion try this;

 $ mplayer -vc help | grep h26.
 geoh264     vfw       working   GeoCodec h264  [GX264.dll]
 ffh264      ffmpeg    working   FFmpeg H.264  [h264]
 ffh264vdpau ffmpeg    working   FFmpeg H.264 (VDPAU)  [h264]
 ffh264crystalhd ffmpeg    working   FFmpeg H.264 (CrystalHD)  [h264_crystalhd]
 ffh264vda   ffmpeg    working   FFmpeg H.264 (VDA)  [h264_vda]
 geoavc      vfw       working   GeoCodec h264 AVC  [GXAVC.dll]
 ffi263      ffmpeg    working   FFmpeg I263  [h263i]
 ffh263      ffmpeg    working   FFmpeg H.263+  [h263p]
 ffzygo      ffmpeg    untested  FFmpeg ZyGo  [h263]
 h263xa      xanim     crashing  XAnim's CCITT H.263  [vid_h263.xa]
 ffh261      ffmpeg    working   CCITT H.261  [h261]
 h261xa      xanim     problems  XAnim's CCITT H.261  [vid_h261.xa]
 m261        vfw       untested  M261  [msh261.drv]
 qth263      qtvideo   crashing  Win32/QuickTime H.263  [QuickTime.qts]
 vssh264     dshow     working   VSS H.264 New  [vsshdsd.dll]
 vssh264old  vfw       working   VSS H.264 Old  [vssh264.dll]

No H.265 which we already knew but now extra confirmation as well as a bunch I've never even heard of.

Life is good,
Maurice

... Weorša še selfne godum d‘dum, šenden šin God recce.
    Bring honour to yourself with good deeds, while God guides you.
--- GNU bash, version 5.1.8(1)-release (x86_64-motorshed-linux-gnu)