FEATURES NAME::patch test/join test.(in attached AniGif the placement of such a button is blinking in the lower left)
avidemux join or patch test (rev2018 to 2021)-.gif
IDEA:: To create test joinings of 2 or more clips to see if results can play or create a visual conflict (image breaking/distorted or grayed out).
DESCRIPTION:: After one enters 2 or more files to be joined the "patch test" text pops up from greyed out to black outlined grey. If one tics ON this choice Avidemux selects the last 5 secs of each file entered (If original clip is less than 5 secs Avidemux will choose whatever it full length is and show a pop up "5 sec? go make a gif instead"[humour]. Each of those 5 secs is joined with the already chosen settings/filters. The output then is played to see if the joinings are compatible.
REASONING:: In this manner instead of joining 6 clips each of 5 minutes thus taking 30 minutes to process (under default priority of "below normal") and finding out mins later that the setting in one of the videos technical makeup (some conflicting settings / tweaks are not noticeable in the video-info tooltips thus don't know till the joining fails) caused the entire joining not to play correctly. In joining the 5 sec test clip in a min or less one knows there is conflict right away and can test the different combinations to figure out which clip has the issue.
Thank You for creating Avidemux and maintaining its professional qualities.
Please use a current version (preferably the latest nightly build (https://avidemux.org/nightly/), else the 2.7.8 release) of Avidemux. At least for H.264 and HEVC video streams, a whole lot of checks was added to reject incompatible source videos when in copy mode.
BTW: Please don't use MP4v2 muxer, it is deprecated. Use the MP4 muxer instead.