Any Format ?

[Beelucky]

Perhaps format to mp3 or ogg that little size bitrate

[ChaoticNeutralCzech]

The audio is stored as AAC in the MP4 container, which should ideally have an m4a extension, as I outlined in Issue 148. AAC is about 2x better than MP3 in terms of quality/bitrate, and almost as good as OGG. So I think that your issue is not really relevant, however if you want to add an option for MP3, which is an older but slightly more compatible recording format, you can make that a new issue.

For reference, relevant MediaInfo lines for the audio stream in sample recordings with the "High-Quality" option off and on:

Property	LQ	HQ
Format	AAC	AAC
Format_AdditionalFeatures	LC	LC
CodecID	mp4a-40-2	mp4a-40-2
BitRate_Mode	CBR	CBR
BitRate	13500	192000
BitRate_Nominal	12200
Channels	1	1
ChannelPositions	Front: C	Front: C
ChannelLayout	M	M
SamplesPerFrame	1024	1024
SamplingRate	8000	44100
FrameRate	7.812	43.066
Compression_Mode	Lossy	Lossy
Title	SoundHandle	SoundHandle
Language	en	en