7fe1ecefe1
Parse expression only when a new value is explicitly specified. In particular, avoid double free in case an old expression value is cached, it is set in the context, it is freed as the old value, and finally the pointer stored in the context is freed again when the filter is released.
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.