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Audio segment is not in alignment with Video segment

ngoc.le@vietcoms.com

Total Posts:
Joined: December 12, 2016

Hi,
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,

NgocL


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

timescale="32000"
(S t="47399836582912" d="64512" r="892")


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

timescale="25"
(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