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• writing custom codecs for android using FFmpeg

  22 mai 2014, par Aditya Kumar Praharaj

  I am doing a video compression project for Android and I am thinking of implementing it by designing a new video codec (by scratch , I have designed the algorithm) . I have already read the basics of video compression , related relevant algorithms and codec basics . I have also found that FFmpeg may serve as a quite good solution on Android.

  Now my questions come :

  1. How to write a new video codec as in FFmpeg ? I am still a beginner at writing codecs , but
     how do I start ? I have a rough idea that that you have to write at least a demuxer first and then the specific encoder and decoder etc . (Asking for references here please.)

  2. Since my codec deosn’t simply adjust video properties like fps , resolution , bit-rate etc.
     Is reading the MediaCodec API and MediaPlayer API in official Android SDK enough for writing new codecs ? (Because last time I saw it had only support for MPEG-4 SP , H.263 and H.264 . I was unable to find if you could directly write your own classes and functions).

  Thanks .

• arm64 : replace ’bic’ with immediate with ’and’ with inverted immediate

  8 décembre 2016, par Janne Grunau

  arm64 : replace ’bic’ with immediate with ’and’ with inverted immediate
  The former is not an official pseudo instruction although gas and llvm’s
  
  internal assembler support it. Fixes a build error with xcode 6.2
  
  reported by Memphiz on github.
  

  • [DBH] libavcodec/aarch64/synth_filter_neon.S

• Subtitles aren't being burnt into the video | embedding srt into video frames [closed]

  29 février 2024, par X3R0

  Describe the bug

  


  I'm trying to burn a subtitles.srt file onto the video (having the subtitle embeded within the frames themselves)

  


  To Reproduce

  


  both `input.mp4` and `subtitles.srt` are available to the WASM FFMPEG FS
const converted = await ffmpegRef.current.exec([
    '-i', "input.mp4", // Input File
    '-i', 'subtitles.srt',  // Burn subtitles into video
    '-vf', 'subtitles=subtitles.srt',  // Burn subtitles into video
    "output.mp4" // Output File
]);


  


  Expected behavior

  


  The Subtitles should be burned into the video.

  


  Desktop :

  


  

  • OS : Windows 10

  


  • Browser Chrome

  


  • Version 122.0.6261.94 (Official Build) (64-bit) (cohort : M122 Rollout)

  


  


  Additional context

  


  Example extract from the subtitles.srt file

  


  1
00:00:00,280 --> 00:00:01,379
Hi,

2
00:00:01,379 --> 00:00:01,679
and

3
00:00:01,679 --> 00:00:01,980
welcome

4
00:00:01,980 --> 00:00:02,200
to

5
00:00:02,200 --> 00:00:03,220
ClipDrop.

6
00:00:03,799 --> 00:00:03,919
Congratulations

7
00:00:03,919 --> 00:00:04,400
on

8
00:00:04,400 --> 00:00:04,719
being

9
00:00:04,719 --> 00:00:05,040
selected

10
00:00:05,040 --> 00:00:05,259
to

11
00:00:05,259 --> 00:00:05,480
do