It may be useful for you to send these feedback to the developers directly, as constructive information for them to be able to improve their app.
Thanks, that's good to know.
Hmm, I haven't tested video calling in Line yet, since back then in the earlier versions this feature wasn't present. I used WeChat for video calls, followed by Skype... where WeChat was better. Will try to test Line video calling when time permits, but I've got a feeling that the Skype video calling has improved by this time. Quality may also depend on the type of network the phone is connected to for both parties.