I want to add additional audio tracks to the video. When I tried to do this with gpac, it replaced original audio track.
I added an extra audio track with this command:
gpac -i $SRC:#udta_tagc="public.accessibility.describes-video":#udta_name="Spanish (describes video)":#Language=sp
But this command replaces the original audio track with newly added track, which is not what I want. How can I add additional audio tracks but keep original track as default?