Archived copy. This page was recovered from the Internet Archive snapshot of /display/SP/LSDRT4 Out-of-sync Sound and Video in wmv to Video Format-X Migration Results taken on 2012-11-18. The original wiki at wiki.opf-labs.org is being decommissioned.

LSDRT4 Out-of-sync Sound and Video in wmv to Video Format-X Migration Results

lsdrscenario

Created by Bolette Ammitzbøll Jurik on Sep 21, 2011 · last edited by Maureen Pennock · on Jun 29, 2012 (view history) · 5 versions

Collection:

Title	windows media video (wmv) with Danish TV broadcasts
Description	sample of a 4 TB collection In the sample 200 Gbytes windows media video (wmv) with Danish TV broadcasts number of files: 732 average file size: 273 Mb largest file: 1 Gb
Licensing	Sample only available to SCAPE partners that sign licence available at: SCAPE Agreement Sharing testdata with Statsbiblioteket
Owner	The State and University Library, Aarhus (SB)
Dataset Location	https://scape.statsbiblioteket.dk/data/wmv/
Collection expert	Bjarne Andersen (SB)
Issues brainstorm	Migration. We do not want to keep wmv for preservation. Earlier ffmpeg migrations has failed on some files?! Some of the migrated files had sound and video out of sync. Detection of these 'failed migrations' is a QA issue. Is there another tool, which can migrate these files? Or can we fix the out-of-sync files? Step 1: Try migration again with newer updated tools to see if we actually get these out-of-sync errors again?
List of Issues	IS13 wmv to Video Format-X Migration Results in Out-of-sync Sound and Video

Issue:

Title	IS13 wmv to video format-X Migration Results in Out-of-sync Sound and Video
Detailed description	SB does not want to keep the windows media video files for preservation. Earlier attempts at migration using ffmpeg failed on some files. Some of the migrated files had sound and video out of sync.
Scalability Challenge	4 TB collection windows media video (wmv). Number of files ~ 14640. Detecting the out-of-sync files manually is resource demanding.
Issue champion	Gry Elstrøm (SB, External User)
Other interested parties	-
Possible Solution approaches	Try migration again with newer updated tool Develop QA tool, which can detect these out-of-sync error. Note: to evaluate the QA test, manual assessment of passed files is necessary in development, but this should not be necessary in the final solution. Is there another tool, which can migrate these files? Or can we fix the out-of-sync files? KEEPS: * For format migration the following tools are available: Mencoder FFMpeg SoX GStreamer Avidemux
Context	-
Lessons Learned	-
Training Needs	-
Datasets	windows media video (wmv) with Danish TV broadcasts
Solutions	TBD

Evaluation

Objectives	Scalability, automation
Success criteria	The workflow that migrates the files also performs a QA, that convinces us the migrated files do not have out-of-sync errors, and with reasonable performance.
Automatic measures	* process 20 files per hour per node * 99% of files pass automatic QA test
Manual assessment	* any 'failed files' should be checked. They should not be 'false positives' (successful migrations with no out-of-sync errors).
Actual evaluations	links to acutual evaluations of this Issue/Scenario

Solutions:

Title	SO5 Video Migration and QA
Detailed description	In earlier video migrations at SB, we experienced out-of-sync errors. These errors may be due to the sound being shifted. As part of the QA in this workflow, it is therefore explicitly checked if the sound has been 'shifted' and we can find an overlap match. The workflow in short: wmv files are migrated to video-format X (mpeg-2 for example) using FFmpeg QA validation of migrated file format extraction and comparison of properties of original and migrated file to detect any out-of-sync errors, use the xcorrSound QA sound comparison tool to compare the audio of the original and the migrated video file; see SO2 xcorrSound QA audio comparison tool
Solution Champion	Bolette Jurik (SB)
Corresponding Issue(s)	IS13 wmv to Video Format-X Migration Results in Out-of-sync Sound and Video
myExperiment Link	TBD
Tool Registry Link	TBD
Evaluation	TBD

Title	SO2 xcorrSound QA audio comparison tool
Detailed description	The xcorrSound QA audio comparison tool compares the sound waves of the original audio with the migrated audio. The tool uses the cross correlation function to find the overlap match. This will give us a match score (between 0 and 1) and also an offset in the second file for the match if the audio has been shifted in the migration (we have examples of this happening). This is not a full solution, but a part of the workflow in solutions to issues 13 and 21. The tool will be added to the Tool Registry before long.
Solution Champion	Bolette Jurik (SB)
Corresponding Issue(s)	IS13 wmv to WAV Migration Results in Out-of-sync Sound and Video IS21 Migration of mp3 to wav
myExperiment Link	migrationQA SCAPE Web Service Wav File Comparison Workflow
Tool Registry Link	xcorrSound
Evaluation	The accuracy of the comparison has only been tested in small scale, but larger tests with known data are planned. The testbed dataset mp3 (128kbit) with Danish Radio broadcasts which is the basis of issue IS21 Migration of mp3 to wav consists of two hour mp3 files (average file size: 118Mb). When these two hour files are migrated to WAV, we get an average file size around 1.4Gb. In February 2012 the migrationQA workflow did not scale nicely to these two hour sound files, but we have run a test on a file cut to 12Mb (about a tenth of the original size) using dd. The Mp3 to Wav Migrate Validate Compare Workflow (see SO4 Audio mp3 to wav Migration and QA Workflow) used only 34 seconds on the cut file. The migration and the file format validation were successful, but the property comparison reported that the files were not 'close enough'. The reason for this is that cutting the file does not change the header information, so the duration of the original cut file is supposedly 2 hours, 2 minutes and 5.23 seconds, while the duration of the migrated file is 13 minutes and 6.38 seconds. Playing the original cut mp3 using the MPG321 Play mp3 to Wav SCAPE Web Service Workflow (see SO4 Audio mp3 to wav Migration and QA Workflow) used 11.7 seconds. The migrationQA SCAPE Web Service Wav File Comparison Workflow took 1.4 minutes. The result was also negative, but an inspection of the output showed that only the last chunk differed, which probably means that FFmpeg and MPG321 handled the cut off differently. We will do some additional tests to get an estimate of performance.