Bug 54857 - FILEOPEN: slow opening, 2Mb .PPT file opens several minutes
Summary: FILEOPEN: slow opening, 2Mb .PPT file opens several minutes
Status: NEW
Alias: None
Product: LibreOffice
Classification: Unclassified
Component: Impress (show other bugs)
(earliest affected)
3.3.4 release
Hardware: All All
: medium major
Assignee: Not Assigned
Keywords: filter:ppt, haveBacktrace, perf
Depends on:
Blocks: File-Opening PPT
  Show dependency treegraph
Reported: 2012-09-13 10:47 UTC by sasha.libreoffice
Modified: 2021-09-21 14:56 UTC (History)
7 users (show)

See Also:
Crash report or crash signature:

ppt file that demonstrates slow opening (2.18 MB, application/vnd.ms-powerpoint)
2012-09-13 10:47 UTC, sasha.libreoffice
minimal reproducer (332.50 KB, application/vnd.ms-powerpoint)
2016-05-16 18:12 UTC, David Tardon
Callgrind output from 5.5 master (8.75 MB, application/x-xz)
2017-05-24 10:56 UTC, Buovjaga
ppt saved in excel 2016 in pptx-format (241.00 KB, application/vnd.openxmlformats-officedocument.presentationml.presentation)
2020-03-10 17:33 UTC, paulystefan
perf flamegraph (1.13 MB, application/x-bzip)
2020-03-23 18:05 UTC, Julien Nabet
perf flamegraph (926.62 KB, application/x-bzip)
2021-04-16 17:22 UTC, Julien Nabet

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Description sasha.libreoffice 2012-09-13 10:47:19 UTC
Created attachment 67096 [details]
ppt file that demonstrates slow opening

Small (about 2 Mb) ppt file opens in Impress several minutes 
Reproduced in 3.3.4 and 3.6.1 on Fedora 64 bit, Core2 Duo 1.8 Ghz
and in 3.4.3 on Windows 7 32 bit, Core2 Duo 2.3 Ghz

What is interesting, the same document saved as pptx in msOffice, opens in Impress immediately.
Comment 1 A (Andy) 2012-12-27 20:34:05 UTC
reproducible with LO (Win7 Home, 64bit, i5, 4GB)

with LO it takes more than 3 minutes to open the file
with Powerpoint 2007 the file is opened within a few seconds
Comment 2 tommy27 2014-01-02 17:43:33 UTC
reproducible with LO (Win7 Pro, 64bit, Intel Core 2 Duo, 4GB RAM)
Comment 3 Joel Madero 2015-05-02 15:42:00 UTC Comment hidden (obsolete)
Comment 4 Buovjaga 2015-06-20 14:42:18 UTC

Win 7 Pro 64-bit Version:
Build ID: 3ecef8cedb215e49237a11607197edc91639bfcd
TinderBox: Win-x86@62-merge-TDF, Branch:MASTER, Time: 2015-06-19_23:16:58
Locale: fi-FI (fi_FI)
Comment 5 Robinson Tryon (qubit) 2015-12-09 18:07:55 UTC Comment hidden (obsolete)
Comment 6 David Tardon 2016-05-16 08:26:49 UTC
Is it possible to create a minimal reproducer, ideally with a single slide?
Comment 7 David Tardon 2016-05-16 18:12:01 UTC
Created attachment 125098 [details]
minimal reproducer
Comment 8 QA Administrators 2017-05-22 13:40:11 UTC Comment hidden (obsolete)
Comment 9 tommy27 2017-05-24 04:27:48 UTC
still reproducible under Win8.1 x64 using LibO

the "minimal reproducer" test files takes ages to open.
Comment 10 Buovjaga 2017-05-24 10:56:43 UTC
Created attachment 133508 [details]
Callgrind output from 5.5 master

Arch Linux 64-bit, KDE Plasma 5
Build ID: 6b5fc059543c16759abd5eec2576b5b68e96883a
CPU threads: 8; OS: Linux 4.10; UI render: default; VCL: kde4; 
Locale: fi-FI (fi_FI.UTF-8); Calc: group
Built on May 21st 2017
Comment 11 QA Administrators 2019-05-24 02:56:40 UTC Comment hidden (obsolete)
Comment 12 Buovjaga 2019-09-21 15:18:36 UTC Comment hidden (obsolete)
Comment 13 paulystefan 2020-03-10 17:33:37 UTC
Created attachment 158568 [details]
ppt saved in excel 2016 in pptx-format

workaround load pptx

save ppt in PowerPoint 2016 as pptx.

Load time in LO x64 in win 10-64 with start about 5 seconds.
Load time in LO x64 in win 10-64 with start about 12 seconds.
Comment 14 Xisco Faulí 2020-03-23 11:35:24 UTC Comment hidden (obsolete)
Comment 15 Julien Nabet 2020-03-23 18:05:23 UTC
Created attachment 158896 [details]
perf flamegraph

Here's a Flamegraph retrieved on pc Debian x86-64 with master sources updated today.
Comment 16 paulystefan 2020-06-20 18:55:31 UTC
in 7.0.0beta2 x64 on win10x64

problem not solved

saved as MSO 2016 ppt, then file size increase, the problem in LO70b2 not changed

only saved as MSO2016 PPTX, then there is no problem.
Comment 17 Roman Kuznetsov 2021-04-14 19:28:50 UTC
still repro in

Version: (x64) / LibreOffice Community
Build ID: 77419c6f3aba1fd5b1660795923c22a39bdb1bad
CPU threads: 4; OS: Windows 6.1 Service Pack 1 Build 7601; UI render: Skia/Raster; VCL: win
Locale: ru-RU (ru_RU); UI: ru-RU
Calc: CL
Comment 18 Julien Nabet 2021-04-16 17:22:11 UTC
Created attachment 171244 [details]
perf flamegraph

Here's a new Flamegraph retrieved on pc Debian x86-64 with master sources updated today + gen rendering (I didn't check if it was different from the one from 2020)
Comment 19 Julien Nabet 2021-04-16 17:23:02 UTC Comment hidden (obsolete)
Comment 20 Noel Grandin 2021-04-29 13:47:09 UTC
We load the PPT, then convert/render every single slide to an image, then load those images as an ODF slide deck.

Fixing this would require someone to fund fairly substantial investment into the PPT import code.
Comment 21 Roman Kuznetsov 2021-09-21 14:56:06 UTC
Still repro 

1 min 30 sec in

Version: (x64) / LibreOffice Community
Build ID: 47a8a65022e3fd7624c95d0341b4809aad11fddb
CPU threads: 8; OS: Windows 10.0 Build 19043; UI render: Skia/Raster; VCL: win
Locale: ru-RU (ru_RU); UI: en-US
Calc: threaded