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• Using ffmpeg with AIR

  19 novembre 2016, par Will Tower

  Does anyone have experience using ffmpeg with AIR ? I have been able to load and play a video but I have not been able to communicate with ffmpeg through stdin in order to control the stream – to seek, pause, etc.

  Apparently I need to use filters to communicate with a running instance of ffmpeg but I am struggling with the syntax (or else am misinformed

• Video Frame Skipping Issues During Chunking and Uploading in React Native App

  24 février 2024, par Kishore J

  To create a social media platform like Instagram and Facebook, we have incorporated the functionality for users to upload reels-style videos. To enhance the viewing experience, we have implemented a strategy to segment these videos and upload them to the backend.

  


  To achieve this, we have employed the ffmpeg-kit-react-native and rn-fetch-blob libraries to segment videos efficiently. We've written an asynchronous function, chunkVideo, which chunks the input video file into segments of a specified duration. Here's a snippet of the code :

  


  async function chunkVideo(inputVideoFile, fileName, segmentDuration = 3) {
try {
  // Define the cache directory path
  const cacheDir = RNFetchBlob.fs.dirs.CacheDir;
  const outputTSFilePattern = `${cacheDir}/${fileName}_video%d.ts`;
  await FFmpegKit.execute(
   `-i ${inputVideoFile} -codec: copy -start_number 0 -hls_time ${segmentDuration} -hls_list_size 0 -hls_segment_filename ${outputTSFilePattern} -f hls ${cacheDir}/index.m3u8`,
  );
} catch (err) {
  logEvent("chunkVideoError", {error: err?.message});
  errorToast(err, true);
  }
}


  


  While this approach works well for segmenting videos, we encountered an issue where some frames are skipping during the chunking process, leading to a compromised viewing experience for the end-users.

  


  How to mitigate the frame skipping problems ?

  


• stream_decoder : fix memory leak after seek table read error

  14 juillet 2016, par Max Kellermann

  stream_decoder : fix memory leak after seek table read error
  When read_metadata_seektable_() fails, the has_seek_table flag is
  
  never set to true, and thus free() is never called.
  Example valgrind output :
   11,185,464 bytes in 1 blocks are definitely lost in loss record 62 of 62
  
      at 0x4C2BC0F : malloc (vg_replace_malloc.c:299)
  
      by 0x4C2DE6F : realloc (vg_replace_malloc.c:785)
  
      by 0x40A7880 : safe_realloc_ (alloc.h:159)
  
      by 0x40A7911 : safe_realloc_mul_2op_ (alloc.h:205)
  
      by 0x40AB6B5 : read_metadata_seektable_ (stream_decoder.c:1654)
  
      by 0x40AAB2D : read_metadata_ (stream_decoder.c:1422)
  
      by 0x40A9C79 : FLAC__stream_decoder_process_until_end_of_metadata (stream_decoder.c:1055)
  It is easy to craft a FLAC file which leaks megabytes of memory on
  
  every attempt to open the file.
  This patch fixes the problem by removing checks which are unnecessary
  
  (and harmful).  Checking the has_seek_table flag is not enough, as
  
  described above.  The NULL check is not harmful, but is not helpful
  
  either, because free(NULL) is documented to be legal.
  After running this code block, we’re in a well-known safe state, no
  
  matter how inconsistent pointer and flag may have been before, for
  
  whatever reasons.
  Signed-off-by : Erik de Castro Lopo <erikd@mega-nerd.com>
  

  • [DH] src/libFLAC/stream_decoder.c