EXTEND transcoding IDR frames

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FordGT90Concept
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Joined: Sat Oct 20, 2018 12:55 pm

EXTEND transcoding IDR frames

Post by FordGT90Concept »

Is there any way to control the EXTEND's transcoding in a way that it outputs all I-frames as IDR frames instead of writing only a single IDR frame at the start?

nickk
Silicondust
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Re: EXTEND transcoding IDR frames

Post by nickk »

It looks like the current configuration is to ensure there is an IDR frame every 2 seconds, but not guarantee every I-frame is an IDR frame.

I will run some tests to see if it makes sense to tweak this.

Nick

softworkz
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Re: EXTEND transcoding IDR frames

Post by softworkz »

For archiving, it is sufficient to have just the initial frame be an IDR frame as a decoder can seek/refer back to that one. Anyway, H.264 allows to do a slice-based "sliding" refresh, where each I-frame refreshes just a certain part of the reference image.

Unfortunately, browsers are rejecting H.264 videos with sliding reference image refresh: https://bugs.chromium.org/p/chromium/is ... ?id=879734
(after remuxing to mp4 container, marking those non-IDR I-frames as key frames, both Chromium-based and Firefox browsers are rejecting those videos, that's what the link describes)

For that reason, it's currently not possible to play EXTEND-encoded videos in those browsers.

sw

nickk
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Re: EXTEND transcoding IDR frames

Post by nickk »

ffprobe is reporting all I frames as key frames in the test recording I did.

What are you using to check?

Nick

softworkz
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Re: EXTEND transcoding IDR frames

Post by softworkz »

I have my own decoding, but I sometimes use:
  • Open Source: http://www.digitalekabeltelevisie.nl/dvb_inspector/
    It's not totally fluent, but many of the better tools are non-free and in the 'free' category, this is pretty good
    But the feature is hidden: you need to right-click the video-pid under the PIDs node and choose "Parse Data". Then you'll get the PES packets decoded in a sub-node.
Can't I post an image here?

FordGT90Concept
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Re: EXTEND transcoding IDR frames

Post by FordGT90Concept »

The new firmware was a great success! :D

nickk
Silicondust
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Re: EXTEND transcoding IDR frames

Post by nickk »

Great - it will be in the next official release.

Nick

softworkz
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Re: EXTEND transcoding IDR frames

Post by softworkz »

By default or will it require some option to be set?

BTW: Thanks a lot for the quick solution!

nickk
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Re: EXTEND transcoding IDR frames

Post by nickk »

softworkz wrote: Mon Jun 07, 2021 11:41 pm By default or will it require some option to be set?

BTW: Thanks a lot for the quick solution!
By default. I-frames were always intended to be IDR on EXTEND.

Nick

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