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• php fread returns empty after one time of execution for popen

  20 avril 2021, par Hamed

  I'm trying to get real-time output from ffmpeg command with popen, but it returns empty after one time of execution in the loop.

  


  &lt;?php&#xA;&#xA;$a = popen(&#x27;ffpb -i mymovie.mp4 -vf subtitles=subtitles.srt mysubtitledmovie.mp4 2>&amp;1&#x27;, &#x27;r&#x27;);&#xA;&#xA;&#xA;while (true) {&#xA;    $b = fread($a, 2096);&#xA;&#xA;    var_dump($b) . "<br />\n";&#xA;&#xA;    ob_flush();&#xA;    flush();&#xA;&#xA;    sleep(1);&#xA;}&#xA;

  


  The output : :

  


  mymovie.mp4:   0%|          | 0/61080.0 [00:00<?, ? frames/s]"
string(105) "Unexpected exception: 'ascii' codec can't encode characters in position 43-47: ordinal 
not in range(128)
"
string(0) ""
string(0) ""
string(0) ""


  


• FFmpeg av_hwdevice_ctx_create returns ENOMEM

  4 mars 2021, par lnogueir

  I am trying to perform h264 video encoding on a GPU using the ffmpeg's vaapi library.

  


  I have been following this example from ffmpeg Github repo.

  


  It fails for me here :

  


  AVBufferRef* vaapi_encoder;
int err = av_hwdevice_ctx_create(&vaapi_encoder, AV_HWDEVICE_TYPE_VAAPI,
                                 NULL, NULL, 0);


  


  This returns -12, which maps to ENOMEM (out of memory) error, but that doesn't make sense to me because I have plenty of memory.

  


  For reference, this is my output after running 'vainfo' :

  


  libva info: VA-API version 1.7.0
libva info: Trying to open /usr/lib/x86_64-linux-gnu/dri/iHD_drv_video.so
libva info: Found init function __vaDriverInit_1_7
libva info: va_openDriver() returns 0
vainfo: VA-API version: 1.7 (libva 2.6.0)
vainfo: Driver version: Intel iHD driver for Intel(R) Gen Graphics - 20.1.1 ()
vainfo: Supported profile and entrypoints
      VAProfileMPEG2Simple            : VAEntrypointVLD
      VAProfileMPEG2Main              : VAEntrypointVLD
      VAProfileH264Main               : VAEntrypointVLD
      VAProfileH264Main               : VAEntrypointEncSliceLP
      VAProfileH264High               : VAEntrypointVLD
      VAProfileH264High               : VAEntrypointEncSliceLP
      VAProfileJPEGBaseline           : VAEntrypointVLD
      VAProfileJPEGBaseline           : VAEntrypointEncPicture
      VAProfileH264ConstrainedBaseline: VAEntrypointVLD
      VAProfileH264ConstrainedBaseline: VAEntrypointEncSliceLP
      VAProfileVP8Version0_3          : VAEntrypointVLD
      VAProfileHEVCMain               : VAEntrypointVLD
      VAProfileHEVCMain10             : VAEntrypointVLD
      VAProfileVP9Profile0            : VAEntrypointVLD
      VAProfileVP9Profile2            : VAEntrypointVLD


  


  Thanks !

  


• libavfilter - reconfigure filter graph using avfilter_graph_parse_ptr returns -22

  16 juillet 2021, par Rahul

  I am using transcode.c sample from ffmpeg examples and it is working as expected. It uses avfilter_graph_parse_ptr to setup filter graph and it works fine.

  


  However, I need change filter graph dynamically and there avfilter_graph_parse_ptr fails. It returns -22. I am not certain if it is a valid operation to do (reconfigure) ? If it is possible, does it require more than avfilter_graph_parse_ptr and avfilter_graph_parse_ptr ? libavfilter documentation doesn't say anything about reconfigure or reset existing graph.

  


  I can create a new graph but I am avoiding it since it is affecting the existing buffers.

  


  Thank you for your insight.