applyAutopadding and withAspect about node-fluent-ffmpeg

[bnerd]

This happens if the input video dimensions are larger then the calculated pad area. ffmpeg throws an error like:

[Parsed_pad_1 @ 0x36df440] Input area 80:0:720:360 not within the padded area 0:0:640:360 or zero-sized
[Parsed_scale_0 @ 0x372fdc0] Failed to configure input pad on Parsed_pad_1
Error opening filters!

I think we should first scale down the video and then apply the pad area in one step, like

-vf scale=640:360,pad=480:360:80:0:0x000000

I did a quick test and combined the scaling and padding in one method

    // add size and pad area in one step
    // video must be scaled down before we apply the pad area!
    if (this.options.video.size && this.options.video.pad && !this.options.video.skip) {
      args.push('-vf');
      args.push('scale=' + this.options.video.size
        + ',pad=' + this.options.video.pad.w +
            ':' + this.options.video.pad.h +
            ':' + this.options.video.pad.x +
            ':' + this.options.video.pad.y +
            ':' + this.options.video.padcolor);
      }

Seems to work so far.

[schaermu]

please test the branch commited above, if everything works we can merge it to the master

[btmdave]

Will this be merged and and updated into npm?

[bencevans]

Would be good to get a test written before this is merged

[njoyard]

On a side note, I'm considering rewriting those size/aspect/padding helpers to only use ffmpeg filters. I'm sick of this dimension calculation code, it is too error prone and ffmpeg filters can do that automagically :)

[bencevans]

I completely agree, the more we can push functionality down into ffmpeg the better.

[njoyard]

I'm closing this because it should have been addressed by #236. Feel free to reopen if you have problems.