HLS and keyframes

[Andoni Morales]

2014-03-06 4:46 GMT+01:00 Dave Walker <dave at happybits.co>:

> I'm experimenting with the HLS plugin, and have found that playback
> behaves much, much better if HLS segments begin with a key frame. Without
> key frames at the beginning I get skipping, dropped frames, and other
> glitches.
>
> I'm wondering why that is? I'm imagining that the HLS demuxer is simply
> responsible for fetching new content and providing it in a continuous
> stream to the next element in the pipeline. If that's the case then the
> exact boundaries between segments wouldn't matter.
>
> I definitely understand that for seeking, keyframes at the start of
> segments is crucial. But I'm just doing live streaming.
>

HLS segment *must* start with a PPS/SPS + Keyframe, this is mandatory in
the spec. Even if you are not seeking and only doing live streaming, the
client will start play at any segment and therefore this segment must be
able to initialize the decoder correctly. You are also switching bitrates,
which means the segment for the new bitrate must also start with a keyframe
for a correct transition.

Cheers,
Andoni

>
> Thanks.
>
> Dave
>
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>
>


-- 
Andoni Morales Alastruey

LongoMatch:The Digital Coach
http://www.longomatch.ylatuya.es
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