Recherche avancée

Sur d’autres sites (10406)

• lavc : add avcodec_free_context().

  5 avril 2014, par Anton Khirnov

  lavc : add avcodec_free_context().
  Right now, the caller has to manually manage some allocated
  
  AVCodecContext fields, like extradata or subtitle_header. This is
  
  fragile and prone to leaks, especially if we want to add more such
  
  fields in the future.
  The only reason for this behaviour is so that the AVStream codec context
  
  can be reused for decoding. Such reuse is discouraged anyway, so this
  
  commit is the first step to deprecating it.
  

  • [DH] doc/APIchanges
  • [DH] libavcodec/avcodec.h
  • [DH] libavcodec/options.c
  • [DH] libavcodec/version.h

• 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

• How to convert a Stream on the fly with FFMpegCore ?

  18 octobre 2023, par Adrian

  For a school project, I need to stream videos that I get from torrents while they are downloading on the server.
When the video is a .mp4 file, there's no problem, but I must also be able to stream .mkv files, and for that I need to convert them into .mp4 before sending them to the client, and I can't find a way to convert my Stream that I get from MonoTorrents with FFMpegCore into a Stream that I can send to my client.

  


  Here is the code I wrote to simply download and stream my torrent :

  


  var cEngine = new ClientEngine();

var manager = await cEngine.AddStreamingAsync(GenerateMagnet(torrent), ) ?? throw new Exception("An error occurred while creating the torrent manager");

await manager.StartAsync();
await manager.WaitForMetadataAsync();

var videoFile = manager.Files.OrderByDescending(f => f.Length).FirstOrDefault();
if (videoFile == null)
    return Results.NotFound();

var stream = await manager.StreamProvider!.CreateStreamAsync(videoFile, true);
return Results.File(stream, contentType: "video/mp4", fileDownloadName: manager.Name, enableRangeProcessing: true);


  


  I saw that the most common way to convert videos is by using ffmpeg. .NET has a package called FFMpefCore that is a wrapper for ffmpeg.

  


  To my previous code, I would add right before the return :

  


  if (!videoFile.Path.EndsWith(".mp4"))
{
    var outputStream = new MemoryStream();
    FFMpegArguments
        .FromPipeInput(new StreamPipeSource(stream), options =>
        {
            options.ForceFormat("mp4");
        })
        .OutputToPipe(new StreamPipeSink(outputStream))
        .ProcessAsynchronously();
    return Results.File(outputStream, contentType: "video/mp4", fileDownloadName: manager.Name, enableRangeProcessing: true);
}


  


  I unfortunately can't get a "live" Stream to send to my client.