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• avcodec/utils : Only call codec->close if init has been called

  24 septembre 2020, par Andreas Rheinhardt

  avcodec/utils : Only call codec->close if init has been called
  avcodec_open2() also called the AVCodec's close function if an error
  
  happened before init had ever been called if the AVCodec has the
  
  FF_CODEC_CAP_INIT_CLEANUP flag set. This is against the documentation of
  
  said flag : "The codec allows calling the close function for deallocation
  
  even if the init function returned a failure."
  E.g. the SVQ3 decoder is not ready to be closed if init has never been
  
  called.
  Fixes : NULL dereference
  
  Fixes : 25762/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_SVQ3_fuzzer-5716279070294016
  Found-by : continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
  Reviewed-by : Paul B Mahol <onemda@gmail.com>
  
  Reviewed-by : Michael Niedermayer <michael@niedermayer.cc>
  
  Signed-off-by : Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
  

  • [DH] libavcodec/utils.c

• Live streaming dash content using mp4box

  15 mai 2017, par galbarm

  I’m trying to live stream H.264 content to HTML5 using the media source extensions API.

  The following method works pretty well :

  ffmpeg -i rtsp://10.50.1.29/media/video1 -vcodec copy -f mp4 -reset_timestamps 1 -movflags frag_keyframe+empty_moov -loglevel quiet out.mp4

  and then :
  mp4box -dash 1000 -frag 1000 -frag-rap out.mp4

  I can take the MP4Box output (out_dashinit.mp4) and send it through Web Sockets, chunk by chunk, to a JavaScript client that feeds it to the media source API.

  However, this is not a good method for live content.

  What I’m trying to do now, is to create a single pipeline in order to do it in realtime and with the minimum possible latency.
  With FFmpeg it’s possible to redirect the output to stdout instead of out.mp4 and grab the content.
  I couldn’t figure out if it’s possible to combine MP4Box into the pipeline.

  1. Can MP4Box take the input data from a source which is not a file ?
  2. Can MP4Box grab such a content progressively (either from a file or other source) while it is arriving in realtime ? i.e. wait a little if stream stops for 1 sec and resume automatically.
  3. Same question but for the output : can it output to something which is not a file (such as stdout) and can it do so progressively so that whenever output data is ready, I will be able to take it and transfer it to the web client, essentially generating a never-ending dashed MP4.

• fftools/ffmpeg : simplify output stream initialization call graph

  25 mars 2023, par Anton Khirnov

  fftools/ffmpeg : simplify output stream initialization call graph
  Several places in the code currently call init_output_stream_wrapper(),
  
  which in turn calls init_output_stream(), which then calls either
  
  enc_open() or init_output_stream_streamcopy(), followed by
  
  of_stream_init(), which tells the muxer the stream is ready for muxing.
  All except one of these callers are in the encoding code, which will be
  
  moved to ffmpeg_enc.c. Keeping this structure would then necessitate
  
  ffmpeg_enc.c calling back into the common code in ffmpeg.c, which would
  
  then just call ffmpeg_mux, thus making the already convoluted call chain
  
  even more so.
  Simplify the situation by using separate paths for filter-fed output
  
  streams (audio and video encoders) and others (subtitles, streamcopy,
  
  data, attachments).
  

  • [DH] fftools/ffmpeg.c
  • [DH] fftools/ffmpeg_enc.c