006e20bd36
This expression is useful to enable/disable overlaying on the fly. Note that this can't be easily done relying on the filtergraph structure, since this implies caching issues or a null frame overlaying in the best case, which is better avoided for performance and convenience reasons.
FFmpeg README ------------- 1) Documentation ---------------- * Read the documentation in the doc/ directory in git. You can also view it online at http://ffmpeg.org/documentation.html 2) Licensing ------------ * See the LICENSE file. 3) Build and Install -------------------- * See the INSTALL file.