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Re: [PATCH] Add optional "&exact=1" CGI arg to show video between keyframes

Maxim Dounin
June 04, 2021 01:40PM
Hello!

On Thu, Jun 03, 2021 at 07:54:49PM +0000, Tracey Jaquith wrote:

> # HG changeset patch
> # User Tracey Jaquith <tracey@archive.org>
> # Date 1622678642 0
> # Thu Jun 03 00:04:02 2021 +0000
> # Node ID 5da9c62fa61016600f2c59982ae184e2811be427
> # Parent 5f765427c17ac8cf753967387562201cf4f78dc4
> Add optional "&exact=1" CGI arg to show video between keyframes.
>
> archive.org has been using mod_h264_streaming with an "&exact=1" patch from me since 2013.
> We just moved to nginx mp4 module and are using this patch.
> The technique is to find the keyframe just before the desired "start" time, and send
> that down the wire so video playback can start immediately.
> Next calculate how many video samples are between the keyframe and desired "start" time
> and update the STTS atom where those samples move the duration from (typically) 1001 to 1.
> This way, initial unwanted video frames play at ~1/30,000s -- so visually the
> video & audio start playing immediately.

So, effectively, this makes invalid streaming requests (not
starting at a keyframe) to return the same data as valid ones
(starting at a keyframe). A properly written player should be
able to achieve the same result by making correct streaming
requests.

Any specific reasons to do this within nginx instead of fixing the
player? Or, given the fact that Flash is effectively dead, by
simply using HTML5 video with appropriate seeking?

--
Maxim Dounin
http://mdounin.ru/
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Subject Author Views Posted

[PATCH] Add optional "&exact=1" CGI arg to show video between keyframes

Tracey Jaquith 204 June 03, 2021 03:56PM

Re: [PATCH] Add optional "&exact=1" CGI arg to show video between keyframes

Maxim Dounin 39 June 04, 2021 01:40PM

Re: [PATCH] Add optional "&exact=1" CGI arg to show video between keyframes

Tracey Jaquith 50 June 04, 2021 10:20PM

Re: [PATCH] Add optional "&exact=1" CGI arg to show video between keyframes

Roman Arutyunyan 45 June 09, 2021 08:12AM

Re: [PATCH] Add optional "&exact=1" CGI arg to show video between keyframes

Tracey Jaquith 46 June 12, 2021 11:46PM

Re: [PATCH] Add optional "&exact=1" CGI arg to show video between keyframes

Tracey Jaquith 54 June 13, 2021 05:54AM



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