Voice notes are extremely high bitrate since version 0.26.11.1733

[Ciancy28]

This almost two year old issue, which still affects to this day the regular android client of telegram, was for some reason also introduced in telegram x starting with this update
see: https://bugs.telegram.org/c/20785
voice notes are now approximately 163 kbps CBR instead of the previous 32 kbps VBR, which is overkill, inefficient and pretty much defeats the point of using the Opus codec in the first place (mp3, which telegram moved away from in 2013, would perform just as good at such bitrates).
this results in waste of bandwidth, and longer voice note upload/download times (which can be especially problematic for users on limited connectivity, a voice message of 5 minutes is now 6 megabytes instead of 1).
whatever caused this change should be reverted, if a (needless in my opinion) quality upgrade was the intent, switching to 48 kbps VBR would suffice.
Keep in mind that the makers of the Opus codec suggest 128 kbps vbr as "pretty much transparent" for fullband stereo music.

[AntoninoScordino]

Telegram-X/app/jni/voice.c

Line 265 in 2e40364

const opus_int32 bitrate = OPUS_BITRATE_MAX;

The change to OPUS_BITRATE_MAX from the proveious configuration should be the reason why voice messages are now encoded at ~163Kbps (although doesn't sound like the maximun bitrate should be ~163Kbps, but higher). This breaking change was introduced on commit 2e40364.

Telegram-X/app/jni/voice.c

Lines 251 to 252 in 63ab962

	const opus_int32 bitrate = 32000;
	const opus_int32 rate = 48000;

If there was indeed a will to improve quality, developers should adapt this change to 48Kbps as proposed by the issue author, rather than fallbacking to OPUS_BITRATE_MAX.