[FFmpeg-devel] [PATCH 2/2] lavc/ratecontrol: Fix error logging for parsing and evaluation of rc_eq

[Michael Niedermayer]

On Fri, Aug 07, 2020 at 11:26:58PM +0200, Alexander Strasser wrote:
> 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 call references the rc_eq string from the context too.
> 
> Signed-off-by: Alexander Strasser <eclipse7 at gmx.net>
> ---
>  libavcodec/mpegvideo.h   | 2 +-
>  libavcodec/ratecontrol.c | 3 +--
>  libavcodec/snowenc.c     | 2 +-
>  3 files changed, 3 insertions(+), 4 deletions(-)
> 
> diff --git a/libavcodec/mpegvideo.h b/libavcodec/mpegvideo.h
> index 29e692f245..d2515a3bbf 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);

what happens if the user sets rc_eq explicitly to NULL ?

thx

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

The day soldiers stop bringing you their problems is the day you have stopped 
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you do not care. Either case is a failure of leadership. - Colin Powell
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