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Topic: how to apply replay gain while converting mp3 speech files to opus (Read 1425 times) previous topic - next topic
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how to apply replay gain while converting mp3 speech files to opus

Hi I am Rupesh from India and I have some mp3 files which are speeches given by someone. These files are recorded at 64 kbps and sample rate from 32000hz and 40000hz. These mp3 files are at very low volume.

I want to convert these files into opus.Previously I have converted these files successfully into opus using db power amp batch converter. I have converted using channel's set to 1 ie., mono and resampling set to 48000hz.When I listened the converted file's audio quality is good but volume is very low.

Someone suggested to apply replay gain directly to mp3 files and then convert to opus.

Which is best between applying replay gain to mp3 files directly after that converting to opus or applying replay gain while transcoding process.

I want to apply replay gain for each file say 10 db individually not to album.

Please suggest how to apply replay gain to mp3 files and store replay gain information in them permanently. Are there any specialized tools for changing volume if so can you suggest which is the best.


Regards,
Rupesh.
Regards,
Rupesh.

Re: how to apply replay gain while converting mp3 speech files to opus

Reply #1
Are you keeping the mp3 files?  Do you really prefer to change the mp3 volume, or would you be happy to just change the volume in the opus files?  Do you even need the opus files?  Transcoding from lossy to lossy is usually discouraged, although you can do it if there is a good reason.

Opus supports modification of the loudness after encoding using a special output gain field that doesn't affect the encoded audio.  It also supports replaygain loudness adjustment using metadata, although that is intended for equalising the loudness of different tracks rather than applying a fixed adjustment to many tracks.  Loudness can also be adjusted during playback in most decoders.

mp3 has its own ways to adjust the loudness of already-encoded audio, either involving replaygain metadata that doesn't change the audio itself, or by actually modifying the audio.  It is usually recommended not to mess with the "original" audio in case you ever want it again to modify in a different way, but that's up to you.  Depending on your transcoding settings, replaygain adjustments from the mp3 may not even be transferred to the opus files (or they might).  My preference would be to adjust the opus files, either giving them all an output gain of +10dB, or even during playback.

Re: how to apply replay gain while converting mp3 speech files to opus

Reply #2
I know that there is quality loss when we convert from mp3 to opus but still I want to convert.

Previously I have converted without replay gain and listened in my android phone and the quality loss is acceptable. I tried to listen in various players including foobar,aimp folder player etc., and in all players I am getting very low volume. I have even tried volume booster and no use.

I have kept a backup in secondary storage the files I want to convert. Applying replay gain in the form of meta data is not acceptable to me because I think all the players available doesn't behave as such.

By applying replay gain by modifying the original files we can get same response from all the players. So please suggest how to apply replay gain to mp3 files permanently., May I know which is the best tool for this purpose.

Actually the source mp3 files consists of only speech doesn't contain any musical instruments output.

Is there any possibility in applying replay gain to opus files during the conversion process not in the form of meta data.
Regards,
Rupesh.

Re: how to apply replay gain while converting mp3 speech files to opus

Reply #3
You might want to ask in the mp3 forum, or whichever tool you prefer to use, about how best to apply your gain the the MP3 files, bearing in mind that it needs to be applied during transcoding so it gets baked into the opus files.

I'd still prefer to apply it to the opus files, but tools are pretty short on the ground.  You can do it in Deadbeef, but I don't know of any other program that will edit the much-vaunted output gain header field.  It is always in bytes 17 and 18 of the header so easy enough to find and edit, and should be applied automatically by every decoder.  Although opusenc has code to set the field, it has no input parameter to enter a value.  Any C programmer could modify this in 5 minutes.

Re: how to apply replay gain while converting mp3 speech files to opus

Reply #4
- Add file to foobar2000

- Hold Shift > right click > ReplayGain > Edit > Save

- Right click file > ReplayGain > Apply to file content

- Convert

Test different things.

Let me add, why don't you try to calculate it automatically first? Maybe the volume is really low and it will adjust by 8-10-12 who knows, again, try and test different ways.

Re: how to apply replay gain while converting mp3 speech files to opus

Reply #5
Yes, whilst in dBpoweramp add the DSP effect Volume Normalize, one of the options is an EBU R128, this will apply the normalization to the actual data whilst is converted.

Re: how to apply replay gain while converting mp3 speech files to opus

Reply #6


    How to obtain same volume while listening to the converted opus file in android phone with headphones.

    I want to get same volume throughout the file I mean I don't want ups and downs while listening to opus file. Is there any DSP to achieve this.

    Suppose while listening to original mp3 source file at point A I got 90 % of maximum volume of my headphones and at point B I got 50% percent of maximum volume of my headphones and at point C I got 95 % of maximum volume. I want to convert to convert this mp3 file to opus file and if I listen this opus file in android phone with headphones I must get say 80 % of maximum volume of my headphones I mean there must be no ups and downs say 90 % at point A, 50 % of maximum volume at point B, 95 % of maximum volume at point C.
Regards,
Rupesh.

 
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