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Checking Tag Synchronization in MPEG-
DASH Content
When Validator processes MPEG-2 transport streams and HLS streams, if the ID3 tag
falls out-of-sync with the audio stream, Validator indicates that Tests 22 and/or 23 failed.
If the input is an MPEG-DASH stream, however, Validator is unable to run tests 22
through 30. For MPEG-DASH content, you can manually check tag synchronization by
using the Nielsen NACAT application in combination with the ID3 tag listing. Just follow
these steps:
1.
Process the MPEG-DASH segments using the -df or -dr option.
2.
Open the detailed tag-listing file. Find the last ID3 tag that includes 2 or more
unstacked EDUs for the same SID. Identify the name of the segment that holds that
tag.
3.
Identify the names of segments that fall 10 to 20 seconds before the segment
identified in step 2. Merge the segment in step 2 with these additional segments (use
copy /b, for example) so that you have a 10-20 second segment of audio.
4.
Open the NACAT application and, with processing turned on, play the audio stream
created in step 3.
5.
In the NACAT history on the main window or in the NACAT log files, note the
watermarks that NACAT identified.
6.
Compare the SIDs and times in the watermarks in NACAT to the SIDs and times of
the EDUs identified in step 2. For watermarks with matching SIDs, the timecodes in
NACAT should fall within 15 to 20 seconds of the timecodes in the ID3 tag EDUs.
Release 1.8 Revision F
61
ID3 Tag Validator Application User Manual
Nielsen Confidential
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