Bug 2200 – Uncompressed exports in formats that have no (realistic) size restriction fail the 4GB trap for WAV & AIFF

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Audacity 3.0.3 development began 19th April 2021

Audacity Bugzilla

Bug 2200 - Uncompressed exports in formats that have no (realistic) size restriction fail the 4GB trap for WAV & AIFF


Summary:	Uncompressed exports in formats that have no (realistic) size restriction fai...

Status:	RESOLVED FIXED

Product:	Audacity
Classification:	Unclassified
Component:	Application Core
Version:	2.3.3
Hardware:	Per OS All

Importance:	P1 RepeatableAll
Assigned To:	Default Assignee for New Bugs

URL:
Keywords:

Depends on:
Blocks:
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Reported:	2019-08-17 09:29 UTC by Peter Sampson
Modified:	2019-08-18 09:40 UTC (History)
CC List:	6 users (show)

See Also:
Steps To Reproduce:	1) create 7 hours of Stereo audio 2) File > Export >Export Audio... 3) Choose "Other uncompressed files" 4) In the Header dropdown select CAF or RF64 5) Save 6) Observe: you wrongly get the error message about WAV and AIFF files being limited to 4GB - and the export is abandoned
Release Note:
First Git SHA:
Group:	---
Workaround:
Closed:	2019-08-18 00:00:00

Flags:	james.k.crook: Must‑Test‑All‑OS- petersampsonaudacity: Regression+ petersampsonaudacity: Test‑OK‑Win+ flyer185: Test‑OK‑Mac+

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Description Peter Sampson 2019-08-17 09:29:40 UTC

When using "other uncompressed files" for exporting audio there are several formats that have effectively unlimited file size due to their use of 64-bit addressing (unlike WAV and AUFF that have a c. 4GB limit due to using 32-bit addressing).

These unlimited size formats are being trapped by the error trap we implemented in 2.3.2 for WAV and AIFF files to ensure that user could not export such files with sizes greater than 4GB (Prior to this Audacity seemed to perform the export, but corrupted the data).

Note too that the error message is totally inappropriate for formats that are not WAV or AIFF which are the only ones mentioned in the error message.

I am not clear on the size restrictions on all the other formats available in the
"Other uncompressed files" Header dropdown - but we should do one of two things:

1) only trap for WAV and AIFF with a 4GB limit - not restricting any other formats.

2) don't trap at all those like CAF and RF64 that are effectively of unlimited size - but ascertain proper size limits for the other formats and apply those with suitable error traps.

We could do 1 as a short-term fix - and do 2 gradually - 1 is what we had for all such formats prior to 2.3.2. See following posting for notes from Steve re. size restrictions

We could also consider removing some of those formats as some would appear to be legacy formats.

This issue was originally reported on the Forum by a user: https://forum.audacityteam.org/viewtopic.php?f=47&t=106362&p=375602

This bug is a regression on 2.3.1 and all earlier Audacity versions - hece a P1 rating

Comment 1 Peter Sampson 2019-08-17 09:33:40 UTC

waxcylinder wrote: 
>Does anybody know the actual size limit for RF64 
Steve replied
>Wikipedia says "approximately 16 exabytes".
>2^64 bytes works out as 15.9999999967 exabytes, so the figure will be 
>very close to 16 exabytes.
>
>CAF files also use 64-bit addressing, so they are probably also about 16 
>exabytes max.

waxcylinder wrote:
>do we consider 16 exabytes to be so big as not worth bothering with 
>an error trap ? 
Steve replied:
>Yes. 16 exabytes is over 16 million terabytes, which is more than a 
>million times bigger than the biggest hdd currently available.
>
>In practical terms, both RF64 and CAF can be considered to have no size limit.


Steve wrote:
>The maximum size of RAW files are limited only by the underlying file system. >For NTFS, that is "approximately 16 exabytes".
>
>W64 has a 64 bit header, so I think that can also be considered to >have "unlimited" file size.
>
>MAT4 and MAT5 supports files bigger 4GB, though I don't know what the actual
>limit is. Audacity shouldn't limit MAT4 or MAT5 to 4 GB.
>
>The other formats appear to be "legacy formats". Legacy applications that
>require these formats are probably limited to 4 GB or less even if the 
>format supports bigger files.

Comment 2 Steve Daulton 2019-08-17 10:10:18 UTC

(In reply to Peter Sampson from comment #0)
Peter wrote:
> We could also consider removing some of those formats as some would
> appear to be legacy formats.

I don't think that we should remove "legacy formats". Audacity is the go-to tool for some users when they need an audio file in an oddball/legacy format.

Comment 3 James Crook 2019-08-17 11:36:37 UTC

DEVEL - FIX MADE
https://github.com/audacity/audacity/commit/da5d049fa07313e5f9e6f12718ad35c7df5c2695

Comment 4 Peter Sampson 2019-08-17 12:14:34 UTC

(In reply to James Crook from comment #3)
Testing on W10 with audacity-2.3.3-alpha-320-da5d049fa07313e5f9e6f12718ad35c7df5c2695

Tested large project (8.5 hours stereo) Exports with full export and reimport fot
CAf RF64 and RAW formats - all worked properly (but I note that RAW offers by dafault a codec that doesn't work - I'll log that as a separate low P bug).

Tested several of the other formats but cancelled after the export started (6 mons per export) but none were trapped with the 4GB trap.

tested WAV and WAVEX - both were properly trapped and reported upon by the 4GB trap.


I can't test AIFF under "Other uncompressed …" - as it is not an available option on Windows.

But looks good to go on W10

Comment 5 Cliff Scott 2019-08-17 15:29:18 UTC

Tested on MacOS 10.14.6, Commit: da5d04 and all works normally even AIFF from the Uncompressed File list. RF64 exports and imports properly with over 4GB file size.