Audio quality is reduced when converting

Hi there, I’m Gin. Please, if possible, could I get some simple, non-jargon help. My mum died in May, she was a singer. We have many cassette tapes of her singing, which many in our local area would love to hear, so I came up with a plan. I would digitize the cassettes using Audacity audio software and then convert the audio file into a video file with an added photo or 2 for a bit of colour and then upload them to a registered channel on Youtube where they would be available for all to access. The trouble is, when I convert the digitized audio file to a video file, the audio quality became horrible, much less clear and bright, in fact, almost a bit muffled. I used Powerpoint for the conversion, from an MP3 in to an MP4 file. I feel there is no point in doing this lengthy project if the beautiful music is ruined at the end, and I won’t upload if my mum doesn’t sound her best. I need a bit of friendly help from someone to make sure the converted video files are as clear as the original audio files. I am posting these files on to Youtube rather than any other platform because they will be accessed by primarily older people with limited knowledge of the internet, but everyone knows and understands Youtube. I am happy to take advice on your recommended video editing software and which is best audio file format to use for the process.
I look forward to your help kind regards Ginlane

I used Powerpoint for the conversion, from an MP3 in to an MP4 file.

Don’t use MP3 in production. Try exporting the cassette capture as a perfect quality WAV (Microsoft) 16-bit file and then use that in the video generation.

Google and see if you can talk PowerPoint into a higher quality. Both MP3 and MP4 are compressed formats and have quality adjusters. How large do you want the files versus how high do you want the quality?

PowerPoint is a graphic program with sound only as an afterthought. You’re supposed to stand up in front of an audience and talk over them.

In addition, I think YouTube goes through a conversion process when you post, so you converted and compressed the music three times on the way to publishing.


Maybe you should try HitFilm Express; I’m talking about the process of joining the music with the slideshow, supposing that you already got to digitalize the cassettes into 16 bit WAV (as suggested above). I’m not expert in HitFilm but, How hard can it be?

Export as MP3 and Export as Wav are right next to each other in the Audacity File menu.

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There is always additional damage with transcoding or re-encoding to a lossy format but it shouldn’t be THAT bad if you use a high bitrate/quality setting.

BTW - When you open a compressed file in Audacity or any “normal” audio editor it gets decompressed. If you re-export in the same lossy compression format it goes through another generation of lossy compression, and the “damage” does accumulate. Multiple generations of MP4 suffers much less accumulated damage than MP3s.

No (additional) damage occurs during decompression (and it will be decompressed when played anyway) so there is no further damage if you export to WAV or FLAC.

If you don’t have a lossless original then the goal is to minimize the number of times it’s re-compressed.

There are special-purpose audio editors such as MP3directCut that can do some limited editing without decompressing/re-compressing.

I am happy to take advice on your recommended video editing software and which is best audio file format to use for the process.

I’m currently using CyberLink PowerDirector and I’ve also used Corel VideoStudio. They are similar and I would NOT “highly recommend” either one, but they usually get the job done. VideoStudio has more audio editing capability. It’s an add-on for PowerDirector. But if I’m doing “serious” audio editing I’ll export the audio and use Audacity or GoldWave, then re-import the audio back into the video editor.

The only reason I switched is that VideoStudio stopped working when I upgraded from Win7 to Win10. Maybe the anti-piracy though I was installing it on a different computer… Both list for around $100 USD but they are almost always marked-down.

There are free trials so if you just have this one job maybe you can get it done during the trial period.

There are usually quality/bitrate settings for both the audio & video and you can use uncompressed LPCM audio (similar to WAV). I assume YouTube will accept the uncompressed audio and then compress to whatever they use. So, you’d only be going through one additional generation of lossy compression.

If you want to use MP4 audio, a higher bitrate means less compression (more bits per second of audio) so that generally gives you better quality. Same goes for the video. A lower bitrate means more data is being thrown-away for a smaller file, but of course resolution also plays a role.

[u]Here[/u] is a list of FREE video editors. (I have not tried them. I use several free audio/video/image tools/utilities, but for video editing or combining audio & video I’ve always used a commercial program.)

If I was going to try a free video editor, I’d probably try Avidemux first because it’s supposed to be “powerful”. As far as I know, none of these free video editors can author a DVD or Blu-Ray. I have a separate (now “outdated”) special-purpose DVD authoring application and I’ve never made a Blu-Ray. You can simply burn an audio/video file onto a disc and many DVD players will play it, but a standards-compliant DVD (usually with a menu) has a very-specific structure/format and it requires DVD authoring software.

she was a singer…
…then upload them to a registered channel on Youtube where they would be available for all to access.

I’m not sure what the current rules are and you may know more than I do, but you may get blocked if the songs are copyrighted (if they are not original songs written by your mother, etc.).

They used to be very strict about this but maybe they’ve changed the policy/agreements and maybe the copyright holder gets paid (from advertising) and they simply restrict you from making money… I don’t know…

Hi, DVDdoug, thanks for your information on copyright in YouTube. The thing is, the songs my mother would sing are pretty old, were not talking about modern stuff that people are gonna get their knickers in a twist about. I’ll be careful, but I don’t imagine it will be a problem

Thank you everyone who has posted, I’m going through all the information you have given me and will see what works
kind regards Gin

Hi again, it’s amateur hour over hear, I’m a complete beginner, I’ve watched a few audacity tutorials to help me improve some 40 year old amateur audio singing recordings which were originally on cassette. Specifically I took the knowledge from this YouTube video:

So this is what I’ve been doing. I used, in order:

Noise Reduction, (If you have a particularly noisy piece of audio you can change the value in the noise reduction DB box to between 12 to 18) then hit okay)
then Compressor, then Normalise, then Equalisation, Select curve, Bass boost,
then Equalisation, Select curve, Treble boost,
then Bass and treble, (Adjust the sliders as desired, you can preview if needed)
then Limiter, limit to -4 dB, and finally, Amplify
I find that after applying all of these settings and then playing my track through my widescreen TV speakers, I have a kind of crackly distorting buzz at the high end of the audio. (I have sent a short WAV clip with this post for your perusal) Now when I just play the audio through my computer, well then the buzz is not there and the same with headphones, it’s only through my widescreen TVs speakers that the distortion happens. I’m afraid my audio will not bear being played through big speakers which sucks! it’s a classic case of a little bit of knowledge is a dangerous thing. Please can someone help me to find a solution to this problem, maybe giving me an idea which of those settings it was which caused this problem in the first place. Ongoing, I am digitising more old cassette tapes and attempting to improve the sound quality. I don’t want to make things worse during restoration so I’d like to figure out a non-distorting way of improving my recordings!

Kind Regards Gin