Video thumbnail rotation

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flatfield
Posts: 9
Joined: Fri Dec 06, 2019 6:39 am

Video thumbnail rotation

Post by flatfield »

Hello everyone,

with xnviewmp 0.94.2 (16 bit version) I have an issue with video thumbnail rotation. In particular example, it is a video taken with an iPhone selfie cam which has "Rotation=180" in its metadata. VLC plays the video in its correct orientation, also the video thumbnail in Windows explorer has the correct orientation.

But the video thumbnail in xnviewmp is upside down. Could it be that the "Rotation" tag is not evaluated for video thumbnail creation in xnviewmp?

Thanks,
Georg
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xnview
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Re: Video thumbnail rotation

Post by xnview »

could you send me a video sample?
Pierre.
flatfield
Posts: 9
Joined: Fri Dec 06, 2019 6:39 am

Re: Video thumbnail rotation

Post by flatfield »

Hi Pierre,

I sent you two small sample vids via email (one for portrait mode, one for 180 degs rotation).

Thanks a lot for looking into this.

Best,
Georg
flatfield
Posts: 9
Joined: Fri Dec 06, 2019 6:39 am

Re: Video thumbnail rotation

Post by flatfield »

Hi Pierre,

did you have a chance to look into this?

Thanks a lot,
Georg
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xnview
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Re: Video thumbnail rotation

Post by xnview »

currently i have no way to fix it, i'll ask FFMPEG team
Pierre.
flatfield
Posts: 9
Joined: Fri Dec 06, 2019 6:39 am

Re: Video thumbnail rotation

Post by flatfield »

Hello Pierre,

what's your call to ffmpeg to create the thumbnails?

I have tried

Code: Select all

ffmpeg -i input.MOV -ss 00:00:00.0 -vframes 1 out.jpg
as well as

Code: Select all

ffmpeg -i input.MOV -vf thumbnail -frames:v 1 out.jpg
on my local build of ffmpeg, and the output has the right orientation for the sample videos I sent you.

Please also note, it is not an issue with ALL portrait mode videos. For example, portrait mode videos edited with splice on my iPhone, do have the correct thumbnail orientation in xnviewmp.

Thanks and best regards,
Georg
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xnview
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Re: Video thumbnail rotation

Post by xnview »

i use QtAV based on ffmpeg not ffmpeg
Pierre.
flatfield
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Joined: Fri Dec 06, 2019 6:39 am

Re: Video thumbnail rotation

Post by flatfield »

Hello Pierre,

is there a statement from the QtAV team regarding this bug?

Thanks,
Georg
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xnview
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Re: Video thumbnail rotation

Post by xnview »

flatfield wrote: Thu Aug 13, 2020 3:30 am is there a statement from the QtAV team regarding this bug?
i'll contact them
Pierre.
flatfield
Posts: 9
Joined: Fri Dec 06, 2019 6:39 am

Re: Video thumbnail rotation

Post by flatfield »

Hello Pierre,

here are some more observations for a very new video file taken in portrait mode on an iPhone 11 iOS 13.6 and xnviewmp 0.96.4.

1. Playback of the affected video file with xnviewmp's internal player is always in portrait mode, but upside down. Playback with VLC is fine.
2. Interestingly enough, the thumbnail orientation in xnviewmp depends on the percentage the frame is extracted (as configurable in the settings):
  • Generate thumbnail at 0% (my default). Thumbnail is not OK and in landscape mode.
  • Change video thumbnail extraction percentage in Settings>Brower>Thumbnail to e.g. 50%. Perform "Rebuild Thumbnails" for this file. Thumbnail is now OK and correctly displayed in portrait mode.
  • Change back video thumbnail extraction percentage in Settings>Brower>Thumbnail to e.g. 10%. Perform "Rebuild Thumbnails" for this file. Thumbnail is now again not OK and incorrectly displayed in landscape mode.
Maybe this helps in analyzing this. Video file can be provided if required.

Thanks,
Georg
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