[FFmpeg-devel] [PATCH 1/2] docs/filters: add documentation to all existing OpenCL filters
gyandoshi at gmail.com
Fri Aug 3 22:13:56 EEST 2018
On 03-08-2018 08:46 PM, Danil Iashchenko wrote:
> +For most general-purpose filters, no conversion is required.
> +In case a file contains an alpha channel supported by the format, then explicit conversion is a requirement.
This is unclear. So, if the input's pixel format has alpha, we should
convert? to what? In the example below, the conversion target also has
alpha. Does RGB24 need to be converted?
> + at item
> +Insert a PNG logo in the top-left corner of the INPUT. Explicit format conversion is a must.
> + at example
> +-i INPUT -i LOGO -filter_complex "[0:v]hwupload[a], [1:v]format=yuva420p, hwupload[b], [a][b]overlay_opencl, hwdownload" OUTPUT
PNGs, afaik, are always full chroma. Shouldn't we convert to yuva444p?
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