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More => Old Versions => Media Center 16 (Development Ended) => Topic started by: rjm on June 05, 2011, 12:06:31 pm

Title: mp3 conversion failure
Post by: rjm on June 05, 2011, 12:06:31 pm
I am attempting to convert a 128 kbps mp3 to Lame V7. I get a conversion failed message but no information on what is causing the problem. I have converted thousands of mp3s in the past without a problem so I suspect something may be wrong with the mp3. I don't see anything unusual except it is large (427 MB) and long (8 hours).

Any suggestions?
Title: Re: mp3 conversion failure
Post by: bob on June 07, 2011, 10:57:46 am
I am attempting to convert a 128 kbps mp3 to Lame V7. I get a conversion failed message but no information on what is causing the problem. I have converted thousands of mp3s in the past without a problem so I suspect something may be wrong with the mp3. I don't see anything unusual except it is large (427 MB) and long (8 hours).

Any suggestions?
I wonder if it's decoding to a wav bigger than 4 gigs (while re-encoding)? Maybe you could test by converting to a wav and see it that works or truncates at 4 gigs...
Title: Re: mp3 conversion failure
Post by: Alex B on June 07, 2011, 06:29:10 pm
If the file is 44.1 Khz stereo the size in 16-bit wave format would be about 4.8 GB. However, that should not matter when piping is used and no temp file is created (= internal encoder). If rjm is using the external encoder option the size of the temp wave file is too big.
Title: Re: mp3 conversion failure
Post by: rjm on June 08, 2011, 12:21:46 am
Thanks Bob and Alex for your help.

Conversion to FLAC reported success and produced a 1 GB file with correct 8 hour duration.

Conversion to WAV reported success and produced a 4.6 GB file with incorrect 1 hour duration.

Conversion to internal MP3 Encoder "-V 7 --vbr-new" (my desired destination) consistently fails.

As mentioned last time, I have successfully converted to "-V 7 --vbr-new" many many times in the past.

Any other ideas?
Title: Re: mp3 conversion failure
Post by: rjm on July 04, 2011, 09:31:21 am
I just observed another conversion failure with a large mp3.

This time a 300 MB 128 kbps 5 hour mp3.
Title: Re: mp3 conversion failure
Post by: bob on July 05, 2011, 10:59:17 am
I just observed another conversion failure with a large mp3.

This time a 300 MB 128 kbps 5 hour mp3.
I'm running some tests. Lame 3.98 in decode mode can't handle the >4gig length in the header. Here is what it outputs:
Frame#971814  32 kbps   MS    Very huge WAVE file, can't set filesize accordingly

Uh oh, from Wikipedia:
Limitations

The WAV format is limited to files that are less than 4 GB, because of its use of a 32-bit unsigned integer to record the file size header (some programs limit the file size to 2–4 GB).[14] Although this is equivalent to about 6.8 hours of CD-quality audio (44.1 kHz, 16-bit stereo), it is sometimes necessary to exceed this limit, especially when greater sampling rates or bit resolutions are required. The W64 format was therefore created for use in Sound Forge. Its 64-bit header allows for much longer recording times. The RF64 format specified by the European Broadcasting Union has also been created to solve this problem.

Title: Re: mp3 conversion failure
Post by: bob on July 05, 2011, 02:09:56 pm
So, that isn't the problem however.
The file re-encoding is stalling at 2 gigs.
You can make it work using the external encoder like this:
Filename: (browse to your lame.exe)
Parameters: --mp3input -V 7 %IN %OUT
Check the "use source file as-is" box
Title: Re: mp3 conversion failure
Post by: rjm on July 05, 2011, 03:54:30 pm
That worked well.

Thanks kindly for your help Bob.