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• How to get iOS App Preview video bitrate in range

  29 avril 2019, par JKaz

  Creating new App Previews for App Store Connect has always been difficult. Time to do it again (new app version) and running into same issue without resolution this time.

  Making the video is easy enough, recording it with Quicktime and either a connected device or through Simulator (and the xcrun simctl io booted recordVideo <filename>.<file extension="extension"></file></filename> Terminal command).

  I can open that in iMovie, create a new App Preview, and export/share the preview with proper size, length, frame rate per Apple specs. But the bit rate is always too low ( 4 mbps) and it’s required to be 10-12 mbps (and I’ve had video reject be/c of that). In the past I could always make some change to the .mp4, in conjunction with something like ffmpeg -i ~/appVideo.mp4 -b:v 11M ~/appPreview.mp4 to get the file into the target range, but that’s not helping today, and neither is Developer Tech Support.

  Apple’s documentation says :

  To export the final video, click Share in the toolbar, then choose App
  Preview. The export settings are automatically configured to meet App
  Store requirements. iMovie exports the final video at the correct
  resolution based on the device from which your clips were captured.

  I’ve done that and more, and bit rate is still out of range (every other attribute is in spec). I’ve tried the recommendations from a bunch of other threads here for http://video.online-convert.com/convert-to-mp4 and others, and none seem to do the trick. Am I missing something obvious re bitrate ? Is it this hard for everyone ?

  Thank you.

• FFmpeg export codec not supported by Samsung

  21 juillet 2021, par Coski

  I am using FFmpeg to render videos (concatenating image files with audio and then applying speed and volume filters) to export videos to upload to TikTok. As a result, I must first move the videos to my phone.

  


  I do not understand why my phone (S20) will happily play one of the videos (codec information pictured first), but presents an error "Codec not supported" when playing the other (information second).

  


  

  


  

  


  The codec information is from VLC, and as you can see, both videos have identical Codecs (H264-MPEG4).

  


  From analysing the information, the only conclusion I come to is that it has something to do with the fact that the "Decoded Format" differs across the videos. How can I change my export command on the latter so my phone supports the codec ?

  


  CONCATENATION CODE
ffmpeg -f concat -safe 0 -i {path_temp}\\clips.txt -c copy -y "{path_temp}\\{title}_a.mp4

  


  FILTER CODE
ffmpeg -i input.mp4 -filter:a "volume={volume}" -y temp.mp4"

  


  SECOND FILTER
ffmpeg -i temp.mp4 -filter_complex "[0:v]setpts={1/speed}*PTS[v];[0:a]atempo={speed}[a]" -map "[v]" -map "[a]" -y output.mp4

  


• Using Qt Media Player on Raspberry Pi 1

  18 mai 2015, par Mauker

  I have a project built using Qt5 which has to play a video. Just like in the videowidget sample code.

  I’ve followed these instructions to build qt5 on my Pi. And it went just fine. But when I try to run any qt program that uses QMediaPlayer, I get the error message :

  defaultServiceProvider::requestService(): no service found for - "org.qt-project.qt.mediaplayer"

  Which means I don’t have a backend to play the video, right ? Is there any one that I can use which will with Qt, like ffmpeg ? And how can I get it to work ? Specially for h264 videos.

  I’ve tried to install gstreamer as is told on this link, but it’s not working. Will I have to rebuild the entire qt5 again ?

  P.S. : I have the raspberry pi 1 model B with raspbian installed.

  Edit : As mentioned by Greenflow, I checked the ./configure log and saw that the GStreamer was compiled in, but the video apps are still not working...

  The message on the log was like this :

  GStreamer .............. yes (0.10)

  And the message on Greenflow’s log was like this :

  GStreamer .............. yes (1.0)

  Clearly it’s another version of GStreamer, but is it the problem ?

  I’ve also found this post which says QtMultimedia on the Pi is rather useless, but the post is from 2013, so I’m not sure if it’s really relevant. I’d like to have this app playing hardware accelerated videos on my Raspberry Pi, but I’m almost dropping the idea.

  Anyways, thanks Greenflow for the head start.

  Edit 2 : Found this thread on the Qtcentre. Damn, this thing is not going to be easy to solve, I guess...