![]() ![]() It's best to start by setting up your command line sequence, then update it to account for ZeroMQ command inputs. we can also use it for scaling and cropping image. Not all FFMpeg filters accept ZeroMQ commands, the ones that do are documented in the documentation FFMpeg Filters, look for 'This filter supports the following commands'. Ffmpeg is a framework use to convert (encode or decode ) video from one format to another format. For example, I use zscale to convert to linear light before downscaling using scale and then I use zscale to convert back to BT.1886 gamma. I find myself using scale for actual image scaling but I do use zscale quite often for colorspace conversions. It also requires installation of ZeroMQ development libraries pre-compilation (also found in the instructions). There are multiple ways to talk to FFmpeg's libswscale library, you're mixing two of them here. ffmpeg -loop 1 -t 10 -i background.jpg -loop 1 -i img1.png -loop 1 -i img2.jpg -loop 1 -i img3.jpg -filtercomplex '1scaleevalframe:w'min(iwt,iw)':h-1img1 2scaleevalframe:w'min(iwt,iw)':h-1img2 3scaleevalframe:w'min(iwt,iw)':h-1img3 0img1overlay(W-w)/2:(H-h)/2:shortest1:formatautobg bgimg2overlayshortest1:formatautobg2 bg2img3overlayW-w:H-h:shortest1:formatauto,formatyuv420p' output. The -enable-libzmq configure flag enables ZeroMQ based filter commands. Refer to my previous post for building on Ubuntu which includes instructions for adding package dependencies and building with what my common feature set Building FFMpeg. The build procedure takes the form of a typical autoconf configure, make, make install. The 0MQ support is optional, not configured by the default configuration, so it likely requires building Ffmpeg from source and configuring it for ZeroMQ support. But, what if you wish to dynamically modify filter parameters dynamically or in real-time? When compiled with ZeroMQ (0MQ) support, some filters can be adjusted in real-time by sending filter commands vi 0MQ. The filter scalars can readily be specified as filter static parameters or in some cases based on time. ![]() For example, to specify temporal scalability parameters with ffmpeg : ffmpeg -i INPUT -c:v libvpx -ts-parameters tsnumberlayers3:\ tstargetbitrate250,500,1000:tsratedecimator4,2,1:\ tsperiodicity4:tslayerid0,2,1,2:tslayeringmode3 OUTPUT. ![]() FFMpeg has a full array of video and audio filters, specify the right parameters and it produces pure magic. ffmpeg -y -i input.mp4 -filtercomplex 'fps1/5,scale320:180' thumbnail-03d.jpg The fps filter is used here to say that we need 1 frame every 5 seconds. Sets the temporal scalability configuration using a :-separated list of keyvalue pairs. ![]()
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