Recherche avancée

Sur d’autres sites (14679)

• using ffmpeg in C : system() or C api ?

  5 décembre 2018, par toastedDeli

  I want to use ffmpeg’s transcoding features multiple times in my program. This can be achieved by doing

  ffmpeg -i input output

  in a terminal. I believe I can use some shell or C code to execute these commands programmatically.

  I could also directly use ffmpeg’s c libraries to do this. My question is, will there be a noticeable performance difference between the 2 approaches ? Obviously the first will be simpler to implement, but will I pay a big performance cost ?

• Compatibility of P-frames and multithreading in FFmpeg library in C

  16 mai 2023, par Rachel

  I am working on a video processing project using the FFmpeg library in C. I would like to inquire about the compatibility and support for utilizing P-frames (predictive frames) and multithreading simultaneously in FFmpeg. Currently, I am exploring two options for achieving multithreading with FFmpeg :

  


  

  1. Setting the i_threads parameter of FFmpeg to a value greater than 1.

  


  2. My application opens multiple threads, where each thread creates a codec context
and performs parallel compression/decompression of frames from a shared FIFO.

  


  


  I have tried option 1, but I did not observe any noticeable time difference compared to using only one thread. I am seeking an understanding of why this might be the case.

  


  I have tried option 2, which has resulted in improved compression/decompression times for the frames. However, I would like to understand why does it work. Since I am utilizing P-Frames, where each P-frame depends on the latest I-Frame, how can I ensure that the decompression of P-Frames starts after the I-Frame has finished processing when dealing with multiple codec contexts ?

  


  I have two proceccses one for encodeing and one for decoding.
I'd like to improve times using threads in both of them.

  


  The encoder process code :

  


  pt_handle->t_x264_param.i_threads = 24;

  


  pt_handle->pt_x264_encoder = x264_encoder_open(&pt_handle->t_x264_param);

  


  The decoder process code :

  


  pt_handle->pt_avcodec_ctx->thread_count = 23;

  


  pt_handle->pt_avcodec_ctx->thread_type = FF_THREAD_FRAME ;

  


  i_retval = avcodec_open2(pt_handle->pt_avcodec_ctx, pt_h264_decoder, NULL);

  


• FFMPEG Using video in to add Watermark

  15 janvier 2021, par Lakhan

  I have tried the below code using my Command line.

  


  ffmpeg -i ed_hd.mp4 -i watermark.png -filter_complex "overlay=20:20" 1610690297-6555.mp4

  


  But didn't works this.

  


  And getting error like that.
The encoder 'aac' is experimental but experimental codecs are not enabled, add '-strict -2' if you want to use it.

  


  tried many times didn't get any success on it. if anyone can help on then I am thankful.