out of sync transcoded and source streams

Wowza Streaming Engine
1

In many cases related to publisher’s internet channel quality arises out of sync source stream and transcoded streams. Output of dvrreporter: https://drive.google.com/file/d/0ByTD7sTTjpACWDdnd2JyR251d2s/edit?usp=sharing

I this case also sometimes stops working dvrreporter for source stream with error: Null

StreamValidator is enable.

2

Yaraslovv,

Try setting a dvrPacketSortTime, as shown in the nDVR Advanced reference

Richard

3

I tried it without success

I think the problem is that the server drops the chunks only on transcoded streams, not on source.

For exapmple:

WARN server comment 2014-04-14 16:15:44 - - - - - 208.283 - - - - - - - DvrStreamStoreBase.storeChunks[live-ror/definst/nature2_480p/nature2_480p.0] : Skipping chunk. A/V durations differ by 2027 ms, more than allowed 2000 ms. aDuration=8777 vDuration=6750

WARN server comment 2014-04-14 16:15:44 - - - - - 208.284 - - - - - - - DvrStreamStoreBase.storeChunks[live-ror/definst/nature2_160p/nature2_160p.0] : Skipping chunk. A/V durations differ by 2027 ms, more than allowed 2000 ms. aDuration=8777 vDuration=6750

WARN server comment 2014-04-14 16:15:44 - - - - - 208.285 - - - - - - - DvrStreamStoreBase.storeChunks[live-ror/definst/nature2_360p/nature2_360p.0] : Skipping chunk. A/V durations differ by 2027 ms, more than allowed 2000 ms. aDuration=8777 vDuration=6750

WARN server comment 2014-04-14 16:15:44 - - - - - 208.285 - - - - - - - DvrStreamStoreBase.storeChunks[live-ror/definst/nature2_240p/nature2_240p.0] : Skipping chunk. A/V durations differ by 2027 ms, more than allowed 2000 ms. aDuration=8777 vDuration=6750

And, then i see out of sync about 10 seconds between source and transcoded streams.

4

I use FMLE with 1500 Kpbs for 1280x720 resolution. The problem is not in out of sync audio and video channels. The problem in out of sync source and transcoded streams. Equal time recording of each streams is very important to be able to use adaptive bitrate streaming. For example, when I create a smil file consisting of transcoded streams, all works fine. When I add in this file sorce stream, and source stream is out of sync with transcoded streams (they have different recorded time), I got a problem with live stream playback using adaptive bitrate

5

The best way to address these audio/video alignment errors is at the encoder level.

What encoder are you publishing with?

What is the bitrate of the source stream?

You might also try adding dvrAllowableAVPacketDelta to the to the DVR/Properties section in Application.xml also found in the guide Richard linked to above.

Salvadore

6

Key frame alignment is critical for adaptive bitrate streaming to work. You can omit the source from the .smil, or you could transcode the source along with the rest of the renditions of the group.

Salvadore