change audio from 128kbit/sec to 32
by Twildd
on
Sep 21, 2006 at 2:47:24 pm
Help! I need advice,
I don't work in Flash, but I am supplying audio files (mp3 files @128 K/bit, 44.1 on a ProTools audio workstation) to a client that is using them in flash for a educational product delivered online.
Question: they want me to change the files from 128 K/bit to 32k/bit. (we are talking several thousand files) Suggestions for them as to workflow?
Can this be achieved on their end by adjusting the Publish settings? or do I need to supply them with new files?
Any help to a complete novice (in FLASH) is most welcome.
Re: change audio from 128kbit/sec to 32 by lajoiet on Sep 21, 2006 at 5:11:59 pm
If they are importing the audio files into the Flash IDE, so that they are embedded into their final SWF files, they can set the MP3 export options to the bitrate they want (but IMO, Flash's bitrate conversion is less than stellar, and it will end up sounding tinny and echoish...)
However if they are loading the MP3s dynamically at run-time, the original MP3 files will need to be transcoded to the lower bitrate. I use a freeware ap called dbPowerAmp to do this and it works great and has a nice fast batch transcoder, but they could also use Audacity (another freebie, but not automated) or any decent audio editor to do the transcoding.
Another point to keep in mind (since it seems they are looking to reduce the file sizes rather drastically) is that Flash can ONLY play files that are encoded at 44.1 kHz. If you give Flash a file that is done at 22kHz, it will play at double speed (I assume you can figure out why this is...) and if you give it a DVD audio file (44.8kHz) it will play just audibly to slow. There is no workaround for this, so whenever you're making MP3s for Flash, they should ALWAYS be 44.1 khz, but you can set the bitrate to whatever you want. I'm not positive, but I think Flash is even OK with 8Bit or 16Bit sampling, but there is no option to the 44.1 sample rate.
>Todd
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I'm filling a need. Without me there would be no bad examples.
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Re: change audio from 128kbit/sec to 32 by Twildd on Sep 21, 2006 at 6:55:36 pm
Thanks for the reply,
If understand what you are saying it does sound like they are loading the Mp3s dynamically. So if that is the case, Is this freeware app. you mentioned any better than the plug-in that I have with Protools?
So... the next question I have to ask is: will I be able to transcode at a lower bitrate with the files I have (.aiff in protools exported as Mp3), will that create huge amounts of work at their end or will it be easier to get the files that they have and bring them into protools and re-export them at a lower Bitrate? This would definitley be a "double compression" situation, but I don't know if it would hurt the quality or not, seems like tests are in order.
Again thanks for your input, I have never never worked in Flash, so I am at their mercy in this case.
Twildd
Re: change audio from 128kbit/sec to 32 by lajoiet on Sep 22, 2006 at 2:02:00 am
dbPowerAmp will transcode just about anything. They have plugins for nearly every audio format I know of, but even better is it will batch process as many files as you want to give it. I've never worked with Protools, but if it has a batch process feature I'm sure it would do an excellent job. Not sure what it uses for an MP3 Codec, but I'm sure it's a good one. If you want to use DB, let me know and I can get you the older Version 9 of the program that came with a free license for the LAME MP3 codec (you have to pay for it with V10 and above) As for double-compression, you're going to such a low bitrate that I don't think it would be a problem. I've used DB for a lot of transcoding (like going from 192kb stereo to 128 mono or similar type MP3 transcoding) and never had any easily noticable audio degradation that isn't expected with droping the bitrate.
>Todd
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I'm filling a need. Without me there would be no bad examples.
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