[FFmpeg-devel] [PATCH] lavc/ratecontrol: Fix error logging for parsing and evaluation of rc_eq

[Alexander Strasser]

Don't pass a potential NULL pointer to av_log, instead use a default
in the rc_eq AVOption definitions. Now the context variable always
holds a string; even if it's the default expression.

Note this also fixes the evaluation error path, where a similar
av_log references the rc_eq string from the context too.
---
 libavcodec/mpegvideo.h   | 2 +-
 libavcodec/ratecontrol.c | 3 +--
 2 files changed, 2 insertions(+), 3 deletions(-)

diff --git a/libavcodec/mpegvideo.h b/libavcodec/mpegvideo.h
index 29e692f245..d3261e3218 100644
--- a/libavcodec/mpegvideo.h
+++ b/libavcodec/mpegvideo.h
@@ -637,7 +637,7 @@ FF_MPV_OPT_CMP_FUNC, \
           "defined in the section 'Expression Evaluation', the following functions are available: "                                                                             \
           "bits2qp(bits), qp2bits(qp). Also the following constants are available: iTex pTex tex mv "                                                                           \
           "fCode iCount mcVar var isI isP isB avgQP qComp avgIITex avgPITex avgPPTex avgBPTex avgTex.",                                                                         \
-                                                                    FF_MPV_OFFSET(rc_eq), AV_OPT_TYPE_STRING,                           .flags = FF_MPV_OPT_FLAGS },            \
+                                                                    FF_MPV_OFFSET(rc_eq), AV_OPT_TYPE_STRING, {.str="tex^qComp"},       .flags = FF_MPV_OPT_FLAGS },            \
 {"rc_init_cplx", "initial complexity for 1-pass encoding",          FF_MPV_OFFSET(rc_initial_cplx), AV_OPT_TYPE_FLOAT, {.dbl = 0 }, -FLT_MAX, FLT_MAX, FF_MPV_OPT_FLAGS},       \
 {"rc_buf_aggressivity", "currently useless",                        FF_MPV_OFFSET(rc_buffer_aggressivity), AV_OPT_TYPE_FLOAT, {.dbl = 1.0 }, -FLT_MAX, FLT_MAX, FF_MPV_OPT_FLAGS}, \
 {"border_mask", "increase the quantizer for macroblocks close to borders", FF_MPV_OFFSET(border_masking), AV_OPT_TYPE_FLOAT, {.dbl = 0 }, -FLT_MAX, FLT_MAX, FF_MPV_OPT_FLAGS},    \
diff --git a/libavcodec/ratecontrol.c b/libavcodec/ratecontrol.c
index 6b77ccd006..03513177f7 100644
--- a/libavcodec/ratecontrol.c
+++ b/libavcodec/ratecontrol.c
@@ -515,8 +515,7 @@ av_cold int ff_rate_control_init(MpegEncContext *s)
             s->avctx->rc_max_available_vbv_use = 1.0;
     }

-    res = av_expr_parse(&rcc->rc_eq_eval,
-                        s->rc_eq ? s->rc_eq : "tex^qComp",
+    res = av_expr_parse(&rcc->rc_eq_eval, s->rc_eq,
                         const_names, func1_names, func1,
                         NULL, NULL, 0, s->avctx);
     if (res < 0) {
--