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• FFMPEG & JNI : How to decode from URL

  24 avril 2013, par Hafedh Haouala

  I'm trying to make an android application that uses the FFMPEG for decoding videos that are not supported by Android ( not on all the devices at least ) : MPEG-TS & h264 Main Profile.
  So, until now, I was able to use FFMPEG from JNI to decode some local video with the above specs, but my goal is to make the FFMPEG decode data from a streaming URL (http://127.0.0.1:1666/) on which I will send buffers from an android service (for certain reasons)

  So, basically, I have two questions :

  • how I will be able to do the decoding from a streaming URL as I couldn't find any good example ?

  • when decoding my local MPEG-TS video, I've noticed that the playback speed is quite slow, and it happen that the video freezes for a while, even the Dolphin Player (based on FFMPEG) has the same behavior, and I don't know if is there some solution for this. Any suggestion ?

  I appreciate your help.

• avcodec/h26[45]_metadata_bsf : Use separate contexts for reading/writing

  6 juillet 2020, par Andreas Rheinhardt

  avcodec/h26[45]_metadata_bsf : Use separate contexts for reading/writing
  Currently, both bsfs used the same CodedBitstreamContext for reading and
  
  writing ; as a consequence, the state of the writer's context at the
  
  beginning of writing a fragment is exactly the state of the reader after
  
  having read the fragment ; in particular, the writer might not have
  
  encountered one of its active parameter sets yet.
  This is not nice and may lead to invalid output even when the input
  
  is completely spec-compliant : Think of an access unit containing
  
  a primary coded picture referencing a PPS with id id (that is known from
  
  an earlier access unit/from extradata), then a new version of the PPS
  
  with id id and then a redundant coded picture that is also referencing
  
  the PPS with id id. This is spec-compliant, as the standard allows to
  
  overwrite a PPS with a different PPS in between coded pictures and not
  
  only at the beginning of an access unit. In this scenario, the reader
  
  would read the primary coded picture with the old PPS and the redundant
  
  coded picture with the new PPS (as it should) ; yet the writer would
  
  write both with the new PPS as extradata which might lead to errors or
  
  to invalid data being output without any error (e.g. if the two PPS
  
  differed in redundant_pic_cnt_present_flag).
  The above scenario does not directly translate to HEVC as long as one
  
  restricts oneself to input with nuh_layer_id == 0 only (as cbs_h265
  
  does : it currently strips away any NAL unit with nuh_layer_id > 0 when
  
  decomposing) ; if one doesn't the same issue as above can happen.
  If one also allowed input packets to contain more than one access unit,
  
  issues like the above can happen even without redundant coded
  
  pictures/multiple layers.
  Therefore this commit uses separate contexts for reader and writer.
  Reviewed-by : Mark Thompson <sw@jkqxz.net>
  
  Signed-off-by : Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
  

  • [DH] libavcodec/h264_metadata_bsf.c
  • [DH] libavcodec/h265_metadata_bsf.c

• FFMPEG Applying Mux Operation to All Files in Folder Structure

  28 septembre 2023, par EURSCVA MembroFoto

  I have two identical folder structures containing video files (containing varying audio channels) - one has the originals, one has proxy (lower res) versions.
The process of making the proxies messed with the sample rate of the audio, so now I need to replace the audio from each proxy clip with the audio of the respective original clip.

  


  It seems like that is something I can do with ffmpeg without transcoding all of the files again :

  


  $ ffmpeg -i original_clip.mov -i proxy_clip.mov -c copy -map 0:0 -map 1:1 proxy_new.mov


  


  The issue is I have no idea how to make this happen for all files in a folder structure, and with the output also ending up in an identical folder structure. Any help is really appreciated, this issue has caused quite a mess...