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• How to call a Rust function that expects a double pointer to buffer

  7 octobre 2020, par Guerlando OCs

  I'm trying to map the following ffmpeg function : http://ffmpeg.org/doxygen/4.0/group__lavc__parsing.html#ga0dd9af605377fcbb49fffd982672d377 to Rust code

  


  int av_parser_parse2    (   AVCodecParserContext *      s,
        AVCodecContext *    avctx,
        uint8_t **      poutbuf,
        int *   poutbuf_size,
        const uint8_t *     buf,
        int     buf_size,
        int64_t     pts,
        int64_t     dts,
        int64_t     pos 
    )   


  


  Here's my Rust code sketch :

  


  fn parse2(
    &self, 
    av_codec_context: CodecContext,
    poutbuf: &mut [u8],
    poutbuf_size: &mut i32,
    buf: &[u8],
    pts: i64,
    dts: i64,
    pos: i64,
) -> Result {
    unsafe {// ptr::null(), ptr::null_mut()
        match av_parser_parse2(self.as_mut_ptr(),
        av_codec_context.as_mut_ptr(),
        poutbuf.as_mut_ptr(),
        poutbuf_size.as_mut_ptr(),
        buf.as_mut_ptr(),
        buf.len() as i32,
        pts,
        dts,
        pos
) {
        }
    }
}


  


  Here's the av_parser_parse2 generated by Rust's C bindings :

  


  pub fn av_parser_parse2(
    s: *mut AVCodecParserContext,
    avctx: *mut AVCodecContext,
    poutbuf: *mut *mut u8,
    poutbuf_size: *mut libc::c_int,
    buf: *const u8,
    buf_size: libc::c_int,
    pts: i64,
    dts: i64,
    pos: i64,
) -> libc::c_int


  


  I'm having problems in 2 arguments :

  


          poutbuf.as_mut_ptr(),
        poutbuf_size.as_mut_ptr(),


  


  How can I make a double pointer ? In ffmpeg the user would provide a pointer to an empty buffer and to a size, which would be ovewritten by the function av_parser_parse2. I think I don't want the poutbuf: &mut [u8], poutbuf_size: &mut i32, arguments. Maybe I need to return a fresh new Vec for every parse2 call ? So the return value for parse2 would be the tuple Vec, i32.

  


  So I think I should take off poutbuf and poutbuf_size from the arguments, and call av_parser_parse2 with something that will become the Vec to return. However, I cannot pass a Vec as a double pointer, because I do not know the size of the returned packet.

  


  How can I deal with the returned buffer ?

  


• How to espace quotes, double quotes and colon inside double quotes when using FFMpeg

  23 septembre 2020, par DnerD.Dev

  I'm trying to get a text written onto a video. I can get it to work when I do it in a single line but not when I need to quote the drawtext inside the double quotes to write two lines.

  


  ffmpeg.exe -i input.ts -vf "[in]drawtext=fontfile=Bebas-Regular.ttf:text='"Day: Sunday"':fontcolor=white:y=(h-h*0.2):x=(w-w*0.95):fontsize=36, drawtext=fontfile=Bebas-Regular.ttf:text='"thing1, thing2, thing3"':fontcolor=white:y=(h-h*0.1):x=(w-w*0.95):fontsize=36[out]" -codec:a copy output1.mp4

  


  I've tried so many combinations of \ but I can't get it to work. The error I get is the following :

  


  Unable to find a suitable output format for 'Sunday':fontcolor=white:y=(h-h*0.2):x=(w-w*0.95):fontsize=36, drawtext=fontfile=Bebas-Regular.ttf:text='thing1,'
Sunday':fontcolor=white:y=(h-h*0.2):x=(w-w*0.95):fontsize=36, drawtext=fontfile=Bebas-Regular.ttf:text='thing1,: Invalid argument


  


  I need the video to have this :

  


  Day: Sunday
Thing1, Thing2, Thing3


  


• FFMPEG with -vf yadif on progressive file produces incorrect 'Original Frame Rate' metadata double

  28 septembre 2020, par hedgehog90

  I've got an ffmpeg command that I often use, I incorporate the yadif argument for content that may or may not be interlaced :

  


  ffmpeg -i input.mkv -c copy -c:v hevc_nvenc -c:a:0 aac -b:a 192k -vf yadif=mode=1:deint=1 output.mkv

  


  This means if input.mkv is an interlaced video, I get double the frame rate and the footage is deinterlaced, and if it's progressive it remains so and the frame rate doesn't change, exactly as I want it.

  


  However, I've just noticed in Mediainfo that progressive videos processed by this command, it adds this mysterious "Original Frame Rate" tag (I assume it's just metadata)

  


  

  


  It doesn't appear to affect playback in VLC or MPV, however it is recognized in MPV as 'framerate (Specified)'...

  


  How do I prevent ffmpeg from generating this tag when using the yadif filter ?