HLS and keyframes

[Dave Walker]

The spec I'm reading seems looser than that:
http://tools.ietf.org/html/draft-pantos-http-live-streaming-12, with SHOULD
language instead of MUST. Particularly in the presence of the new byte
range segments (which I know aren't supported by gstreamer yet) I wouldn't
think it would be desirable to force every segment to have its own PPS/SPS.

But my question is more about the behavior I'm seeing. Would you expect me
to be getting glitches and dropouts with segments that *don't* start with a
keyframe and PPS/SPS? Does the next stage in the pipeline treat each
segment independently, rather than as one big continuous stream? If it's
all one big stream I wouldn't think it would matter where the boundaries
between segments are.

Dave


On Thu, Mar 6, 2014 at 5:34 AM, Andoni Morales <ylatuya at gmail.com> wrote:

>
>
>
> 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
>>
>> _______________________________________________
>> gstreamer-android mailing list
>> gstreamer-android at lists.freedesktop.org
>> http://lists.freedesktop.org/mailman/listinfo/gstreamer-android
>>
>>
>
>
> --
> Andoni Morales Alastruey
>
> LongoMatch:The Digital Coach
> http://www.longomatch.ylatuya.es
>
> _______________________________________________
> gstreamer-android mailing list
> gstreamer-android at lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/gstreamer-android
>
>
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