FFmpeg Items of Note

Quality Option when rendering:

FFmpeg responds variably to the quality option in the render option but seems to respond well to bitrate. The subranges used by quality even seem to vary somewhat depending on how old the codec is. Some use 0 to 35, some use 0 to 500 or so. The quality is supposed to cause the codec to output data until the noise level is below a limit determined by the quality setting. Your specific results may vary.

Previous Changes when rendering:

With ffmpeg there are 2 cases that the defaults will be used. The first time when you have nothing set up and any other time when you reset the render File Format in the Render Menu. Otherwise with ffmpeg, if you change a video compression type for the render (for example h264.mp4 to h265.mp4), the settings will be from the previous session settings.

Outstanding Issues with ffmpeg:

There are some problems that need to be addressed by the ffmpeg developer group that adversely affect CINELERRA-GG. These are stated below with the hopes that that group will fix them as time permits.

• Make all the default parameters operational. When they are not, the CINELERRA-GG plugins can't be initialized since the initial state of the filter is not operational. If that is not possible, then provide a set of nominal parameters for each plugin, so that they can be used as the plugins initial default state.
• Make the filter config function project the new parameter data into the filter function at any point during filter operation. This is so that continuous updates can be done as the plugin operates.
• Improve seek codec restarts. The past predictor must be reset or reconstructed after a seek. The only documented way to seek is open/seek/play. Reopening the format layer is very expensive.