Hi I am Rupesh from India and I have 25 gb of speech files which are recorded by someone at mostly 32 kbps and 64 kbps. I want to convert these mp3 files to opus using foobar.

Actually the file's I want to convert are transcoded by someone from high quality files to low quality files using fhg encoder. I am sure about it because I saw the properties of these files in Windows explorer. They have not encoded the files properly I mean with optimum settings. They have compressed huge files into small mp3 files and distributed freely.

As these mp3 files are not encoded properly I am unable to hear the voice properly instead I am getting noise. For listening these mp3 files it is ok I mean I am able to sacrifice some quality because they are available freely.

I want to convert these files to opus. Previously I have converted to opus using dbpoweramp at 12 kbps vbr, 48000 hz, channels set to mono. Someone suggested to encode atleast at 16 kbps and so I have done using dbpoweramp but still I am unable to hear the voice loudly and so I have added dsp volume normalize and in that I have selected adaptive equalization EBU but the process is taking many hours to encode a single file. So I have decided to encode using foobar by adding some dsps inorder to maintain same volume for all files.

In foobar I can't find any dsp called volume normalize but found Replaygain and in that I found tabs source mode, processing, Preamp. In preamp I found with RG info, without RG info. Are there any separate plugins for volume normalization.

In order to get high quality opus files I am ready to use 24 kbps bitrate. I am new to dsps and so please suggest right settings in order to maintain same volume for all volumes and if possible to reduce noise.