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• Android video color ajustments

  4 octobre 2012, par Christian

  I'm working on an Android app that among other things will allow the users to make short videos, apply funny effects to them and share them with one another. To begin with, i'm looking for simple color-effects like grayscale, brightness, contrast, sepiatoning, and such.

  All this would be very simple by using the camera-class which can apply the color effects at recording-time - at least most phone's cameras can - i've tested some using Camera.getParameters().getSupportedColorEffects();. But the thing is : i need to do it after the recording has been done : the user would open a video, and choose among a set of effects to apply ; then upload that changed video to a shared server.

  I can't for the love of * find a good way to do this.

  Android doesn't seem to include any videoutilities in the sdk. The android.media.effect package can do some effects, but only backdropper for videos, the rest are for images. Extracting bitmaps from the surfaceview of a videoview during playback doesn't work, it just returns an all-black bitmap. It seems like there's no way to intercept the datastream between the storage and the screen. and apply the effects there. I've started to look into using the FFmpeg library to decode a video file so i can get access to the data, but that requires quite a bit of native coding, and also requires separate compiles for various CPU architectures, so it's very messy. I thought that as the camera can apply these effects (on a Sony LT26i : none, mono, negative, solarize, sepia, posterize), perhaps one could feed the recorder with a videostream not from the camera, but from the memory, and by that way use a stored video file ?

  Do anyone know if there is a good way to apply effects to a video - after it has been recorded ?

• Android video color adjustments

  9 octobre 2012, par Christian

  I'm working on an Android app that among other things will allow the users to make short videos, apply funny effects to them and share them with one another. To begin with, i'm looking for simple color-effects like grayscale, brightness, contrast, sepiatoning, and such.

  All this would be very simple by using the camera-class which can apply the color effects at recording-time - at least most phone's cameras can - i've tested some using Camera.getParameters().getSupportedColorEffects();. But the thing is : i need to do it after the recording has been done : the user would open a video, and choose among a set of effects to apply ; then upload that changed video to a shared server.

  I can't for the love of * find a good way to do this.

  Android doesn't seem to include any videoutilities in the sdk. The android.media.effect package can do some effects, but only backdropper for videos, the rest are for images. Extracting bitmaps from the surfaceview of a videoview during playback doesn't work, it just returns an all-black bitmap. It seems like there's no way to intercept the datastream between the storage and the screen. and apply the effects there. I've started to look into using the FFmpeg library to decode a video file so i can get access to the data, but that requires quite a bit of native coding, and also requires separate compiles for various CPU architectures, so it's very messy. I thought that as the camera can apply these effects (on a Sony LT26i : none, mono, negative, solarize, sepia, posterize), perhaps one could feed the recorder with a videostream not from the camera, but from the memory, and by that way use a stored video file ?

  Do anyone know if there is a good way to apply effects to a video - after it has been recorded ?

• ffmpeg png overlay to mp4 color is not correct [closed]

  14 août 2023, par PGT

  I'm trying to overlay some subs on an .mp4 file using the following command :

  


  ffmpeg -y -i count5.mp4 -i subs1.png -i subs2.png \
-filter_complex "[0][1]overlay=enable=between(t\,1\,2):x=0:y=0[out]; \
[out][2]overlay=enable=between(t\,3.5\,4.6):x=0:y=0[out]" \
-map [out] -map 0:a? new.mp4


  


  It works, but the subtitle colors are not correct :
Here is the overlay :

  


  

  


  Here is how it looks on the .mp4 output :

  


  

  


  Looks like it turned a little pink or orange. Maybe the better question is how do I maintain the correct video quality ? I have very limited knowledge of video formats and ffmpeg so not sure where to start debugging or the right keywords to use.

  


  Finder tells me the png is color profile sRGB IEC61966-2.1 and the video is HD (1-1-1)