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Audio segment is not in alignment with Video segment


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Joined: December 12, 2016

We got an issue of Dash playback. Sometime the video freezes after starts in 30mins.
When checking the manifest, i got that the duration of audio segment does not match to duration of video segment

we use Unified-streaming Packager (USP) for MSS ingest then re-package to DASH output.
Elemental Live is used for Transcoder to procedure 5x video streams and 2x audio streams. Audio and video streams are separate.
- Video encoding: Frame rate = 25fps; GOP = 50, closed gop, H264
- Audio encoding: Sample rate = 32Khz, BR= 56Kbps, AAC-LC
- Fragment Length = 2 seconds

USP takes the MSS for ingestion and re-package to DASH output.
In manifest MPD file, Video segmentation is always 2 second. However the audio segmentation is 64512/ 32000 = 2.016 seconde ( not exactly 2s). Then not in alignment with Video. MPD file is attached for your reference.

Can you please support to correct this error of audio segment duration

Many thanks,


--AUDIO Segment Time Line--------------------------------

(S t="47399836582912" d="64512" r="892")

--VIDEO Segment Time Line--------------------------------

(S t="37031122300" d="50" r="899")

Tags: DASH, aligment, audio segmentation
Attachments: MPD_DASH_stag.xml
Posted on December 13, 2016 at 1:41 AM