encoder: mpeg2: add support for tuning parameters
Submitted by Gwenole Beauchesne @gb
Link to original bug (#719708)
Description
This is the MPEG-2 encoding counterpart for bug 719696
Suggested property for vaapiencode_mpeg2:
- "tune": encoder tuning based on usage (default: "none").
- Option: "size" for lower encoded sizes, thus enabling available features from higher profiles, if available. e.g. B-frames, etc.
Tuning options have precedence over indidual MPEG-2 encoding features.