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• play encrypted movies in vlc by decrypting them by ffmpeg "on the fly"

  21 mai 2024, par doctor

  I would like to play encrypted movies in vlc by decrypting them by ffmpeg like below on macOS.
The size of my movie is, say, 200-1000MB. (hundreds of files)

  


  My problem is that it is too slow to decrypt ; it takes 5mins for 300MB movie before it starts to play.
My guess is that ffmpeg first decrypts the whole content of 300MB and then VLC plays it.
My question : Is it possible to play the movie "on the fly" while decrypting it ?
(play the decrypted chunk once it is decrypted, Not wait until the whole movie is decrypted before it plays, so that it starts to play in, say, 10 secs delay.)

  


  ffmpeg -decryption_key 0 -i "movie.locked.mp4" -f matroska | /Applications/VLC.app/Contents/MacOS/VLC - --fullscreen --quiet --play-and-exit


  


• "Error : more samples than frame size" while encoding audio to opus codec using FFMPEG

  28 avril 2023, par lokit khemka

  I am converting audio from codec AAC to Opus using libavcodec library of FFMPEG. The input codec details are as follows : Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, 6 channels, fltp, 391 kb/s (default)

  


  The codec options that I have used for the output encoding are as follows :

  


      int OUTPUT_CHANNELS = 2;
    int OUTPUT_BIT_RATE = 32000;
int sample_rate = 48000;
    encoder_sc->audio_avcc->channels = OUTPUT_CHANNELS;
    encoder_sc->audio_avcc->channel_layout = av_get_default_channel_layout(OUTPUT_CHANNELS);
    encoder_sc->audio_avcc->sample_rate = sample_rate;
    encoder_sc->audio_avcc->sample_fmt = encoder_sc->audio_avc->sample_fmts[0];
    encoder_sc->audio_avcc->bit_rate = OUTPUT_BIT_RATE;
    encoder_sc->audio_avcc->time_base = (AVRational){1, sample_rate};


  


  I am using the code in the file as it is, with minimal changes : https://github.com/leandromoreira/ffmpeg-libav-tutorial/blob/master/3_transcoding.c for reference. Look for the function prepare_audio_encoder in the file.

  


  When the run the program, I keep getting the error : " more samples than frame size". I don't know much about Audio Processing, so I cannot debug this error. Any help is greatly appreciated.

  


• ffmpeg wont "gracefully" terminate using q or kill -2

  24 mai 2023, par Jeff Thompson

  I am trying to run a bash command on Ubuntu to pull video from a stream and make an .mp4 with it. Here is the command I am using.

  


  ffmpeg -rtsp_transport tcp -i 'rtsp://username:password!@ipaddress/?inst=1' -c copy -f segment -segment_time 180 -reset_timestamps 1 ipaddress_day_3_2_%d.mp4

  


  It connects and begins copying the stream fine, the issue comes with trying to stop the process. It states press [q] to stop, which does not work. I have also tried kill -2 pid and kill -15 pid. Where pid is the process id. However kill -9 pid works and ctrl+c works. The issue with killing it this way is it corrupts the .mp4 rendering it useless. This is the error I get when using ctrl+c or kill -9.

  


  av_interleaved_write_frame(): Immediate exit requested   [segment @ 0x56337ec42980] Failure occurred when ending segment 'ipaddress_day_3_2_0.mp4' Error writing trailer of ipaddress_day_3_2_0%d.mp4: Immediate exit requested

  


  One thing to note is pressing [q] did work once, when I first started working on this but has not since.

  


  Thank You.

  


  I have tried kill -2 pid, kill -15 pid and [q], which I expected to "gracefully" terminate it.
kill -9 pid and ctrl+c will forcefully terminate it but corrupt the file.