[Live-devel] Playback Speed

[Mark Bondurant]

I suppose I could intercept the SPS headers and substitute my own, but looking in the spec, I see no field specifying fps. It doesn't seem to me to be in the spirit of the thing being as everything is so variable. GOP's can cover two seconds or half a second. Slices are very arbitrary.

I discovered that the frame rate doesn't seem to really matter to the size of the clips I produce, which makes sense. The reference frame is the big space hog. I set the camera to 30fps, it's max with H264, and VLC Player seemed happy with that. It makes for nice smooth playbacks.

From: live-devel [mailto:live-devel-bounces at ns.live555.com] On Behalf Of PROMONET Michel
Sent: Thursday, December 04, 2014 11:04 AM
To: LIVE555 Streaming Media - development & use
Subject: Re: [Live-devel] Playback Speed

In an H264 elementary stream, the framerate could be defined in the SPS, but this is an optional field (see ISO 14496-10).

Regards,

            Michel.

[@@ THALES GROUP INTERNAL @@]

De : live-devel [mailto:live-devel-bounces at ns.live555.com] De la part de Deanna Earley
Envoyé : mardi 2 décembre 2014 10:14
À : 'LIVE555 Streaming Media - development & use'
Objet : Re: [Live-devel] Playback Speed

H.264 is a video frame encoding format. It has no concept of time.
You need to write out as one of the standard file containers to make a standard file.
I think LiveMedia has sinks for various types like Matroska and MP4.

This will give you the metadata like format, length, framerate, resolution, etc.

--
Deanna Earley | Lead developer | icatchercctv

w: www.icode.co.uk/icatcher<http://www.icode.co.uk/icatcher> | t: 01329 835335 | f: 01329 835338
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From: live-devel [mailto:live-devel-bounces at ns.live555.com] On Behalf Of Mark Bondurant
Sent: 01 December 2014 18:11
To: 'LIVE555 Streaming Media - development & use'
Subject: Re: [Live-devel] Playback Speed

Oh. I didn't know that. I assumed it had to be part of the h264 headers (one or the other). Is there any way, that's comprehensible to my newb video skillset, to add that to my filesink, as in perhaps an example in one of the test programs?

From: live-devel [mailto:live-devel-bounces at ns.live555.com] On Behalf Of Deanna Earley
Sent: Thursday, November 27, 2014 1:07 AM
To: 'LIVE555 Streaming Media - development & use'
Subject: Re: [Live-devel] Playback Speed

Play in what?
Raw H.264 streams have no “speed” encoded with them, so you’d need to find a way to specify that in your player, or use a container (like AVI, mp4, etc) that stores the extra metadata.
The player is probably assuming a 25fps.

--
Deanna Earley | Lead developer | icatchercctv

w: www.icode.co.uk/icatcher<http://www.icode.co.uk/icatcher> | t: 01329 835335 | f: 01329 835338
Registered Office : 71 The Hundred, Romsey, SO51 8BZ. Company Number : 03428325

From: live-devel [mailto:live-devel-bounces at ns.live555.com] On Behalf Of Mark Bondurant
Sent: 25 November 2014 17:23
To: 'LIVE555 Streaming Media - development & use'
Subject: [Live-devel] Playback Speed

I'm encountering a curious problem with payback speed. I'm pulling an RTSP play stream from my cameras, copying the NAL's, prepending them with the start code, as contiguous GOP units straight to disk, headers and all. And they play fine. Just at double speed. The camera is set to NTSC/H264/CIF/12 fps/Constant Bit Rate/0.125 Mbps. Any ideas what I'm doing wrong?


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