[FFmpeg-devel] [PATCH v2] avfilter/vf_delogo: support expr in delogo filter

[Steven Liu]

> 在 2019年8月27日，23:29，Limin Wang <lance.lmwang at gmail.com> 写道：
> 
> On Tue, Aug 27, 2019 at 03:17:09PM +0800, Steven Liu wrote:
>> Signed-off-by: Steven Liu <lq at chinaffmpeg.org>
>> ---
>> libavfilter/vf_delogo.c | 72 ++++++++++++++++++++++++++++++++++++++---
>> 1 file changed, 68 insertions(+), 4 deletions(-)
>> 
>> diff --git a/libavfilter/vf_delogo.c b/libavfilter/vf_delogo.c
>> index 065d093641..cbc7e87a1c 100644
>> --- a/libavfilter/vf_delogo.c
>> +++ b/libavfilter/vf_delogo.c
>> @@ -31,10 +31,52 @@
>> #include "libavutil/imgutils.h"
>> #include "libavutil/opt.h"
>> #include "libavutil/pixdesc.h"
>> +#include "libavutil/eval.h"
>> #include "avfilter.h"
>> #include "formats.h"
>> #include "internal.h"
>> #include "video.h"
>> +static const char * const var_names[] = {
>> +    "x",
>> +    "y",
>> +    "w",
>> +    "h",
>> +    "n",            ///< number of frame
>> +    "t",            ///< timestamp expressed in seconds
>> +    NULL
>> +};
>> +
>> +enum var_name {
>> +    VAR_X,
>> +    VAR_Y,
>> +    VAR_W,
>> +    VAR_H,
>> +    VAR_N,
>> +    VAR_T,
>> +    VAR_VARS_NB
>> +};
>> +#define TS2T(ts, tb) ((ts) == AV_NOPTS_VALUE ? NAN : (double)(ts) * av_q2d(tb))
>> +
>> +static int set_expr(AVExpr **pexpr, const char *expr, const char *option, void *log_ctx)
>> +{
>> +    int ret;
>> +    AVExpr *old = NULL;
>> +
>> +    if (*pexpr)
>> +        old = *pexpr;
>> +    ret = av_expr_parse(pexpr, expr, var_names, NULL, NULL, NULL, NULL, 0, log_ctx);
>> +    if (ret < 0) {
>> +        av_log(log_ctx, AV_LOG_ERROR,
>> +               "Error when parsing the expression '%s' for %s\n",
>> +               expr, option);
>> +        *pexpr = old;
>> +        return ret;
>> +    }
>> +
>> +    av_expr_free(old);
>> +    return 0;
>> +}
>> +
>> 
>> /**
>>  * Apply a simple delogo algorithm to the image in src and put the
>> @@ -156,16 +198,19 @@ static void apply_delogo(uint8_t *dst, int dst_linesize,
>> typedef struct DelogoContext {
>>     const AVClass *class;
>>     int x, y, w, h, band, show;
>> +    char *x_expr, *y_expr, *w_expr, *h_expr;
>> +    AVExpr *x_pexpr, *y_pexpr, *w_pexpr, *h_pexpr;
>> +    double var_values[VAR_VARS_NB];
>> }  DelogoContext;
>> 
>> #define OFFSET(x) offsetof(DelogoContext, x)
>> #define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM
>> 
>> static const AVOption delogo_options[]= {
>> -    { "x",    "set logo x position",       OFFSET(x),    AV_OPT_TYPE_INT, { .i64 = -1 }, -1, INT_MAX, FLAGS },
>> -    { "y",    "set logo y position",       OFFSET(y),    AV_OPT_TYPE_INT, { .i64 = -1 }, -1, INT_MAX, FLAGS },
>> -    { "w",    "set logo width",            OFFSET(w),    AV_OPT_TYPE_INT, { .i64 = -1 }, -1, INT_MAX, FLAGS },
>> -    { "h",    "set logo height",           OFFSET(h),    AV_OPT_TYPE_INT, { .i64 = -1 }, -1, INT_MAX, FLAGS },
>> +    { "x",    "set logo x position",       OFFSET(x_expr),    AV_OPT_TYPE_STRING, { .str = "-1" }, CHAR_MIN, CHAR_MAX, FLAGS },
>> +    { "y",    "set logo y position",       OFFSET(y_expr),    AV_OPT_TYPE_STRING, { .str = "-1" }, CHAR_MIN, CHAR_MAX, FLAGS },
>> +    { "w",    "set logo width",            OFFSET(w_expr),    AV_OPT_TYPE_STRING, { .str = "-1" }, CHAR_MIN, CHAR_MAX, FLAGS },
>> +    { "h",    "set logo height",           OFFSET(h_expr),    AV_OPT_TYPE_STRING, { .str = "-1" }, CHAR_MIN, CHAR_MAX, FLAGS },
>> #if LIBAVFILTER_VERSION_MAJOR < 7
>>     /* Actual default value for band/t is 1, set in init */
>>     { "band", "set delogo area band size", OFFSET(band), AV_OPT_TYPE_INT, { .i64 =  0 },  0, INT_MAX, FLAGS },
>> @@ -194,6 +239,18 @@ static int query_formats(AVFilterContext *ctx)
>> static av_cold int init(AVFilterContext *ctx)
>> {
>>     DelogoContext *s = ctx->priv;
>> +    int ret = 0;
>> +
>> +    if ((ret = set_expr(&s->x_pexpr, s->x_expr, "x", ctx)) < 0 ||
>> +        (ret = set_expr(&s->y_pexpr, s->y_expr, "y", ctx)) < 0 ||
>> +        (ret = set_expr(&s->w_pexpr, s->w_expr, "w", ctx)) < 0 ||
>> +        (ret = set_expr(&s->h_pexpr, s->h_expr, "h", ctx)) < 0 )
>> +        return ret;
>> +
>> +    s->x = av_expr_eval(s->x_pexpr, s->var_values, s);
>> +    s->y = av_expr_eval(s->y_pexpr, s->var_values, s);
>> +    s->w = av_expr_eval(s->w_pexpr, s->var_values, s);
>> +    s->h = av_expr_eval(s->h_pexpr, s->var_values, s);
> 
> it'll memory leak if not to use av_expr_free after uninit I think.
okay, will submit new version patch.
> 
>> 
>> #define CHECK_UNSET_OPT(opt)                                            \
>>     if (s->opt == -1) {                                            \
>> @@ -252,6 +309,13 @@ static int filter_frame(AVFilterLink *inlink, AVFrame *in)
>>     int plane;
>>     AVRational sar;
>> 
>> +    s->var_values[VAR_N] = inlink->frame_count_out;
>> +    s->var_values[VAR_T] = TS2T(in->pts, inlink->time_base);
>> +    s->x = av_expr_eval(s->x_pexpr, s->var_values, s);
>> +    s->y = av_expr_eval(s->y_pexpr, s->var_values, s);
>> +    s->w = av_expr_eval(s->w_pexpr, s->var_values, s);
>> +    s->h = av_expr_eval(s->h_pexpr, s->var_values, s);
>> +
>>     if (av_frame_is_writable(in)) {
>>         direct = 1;
>>         out = in;
>> -- 
>> 2.17.2 (Apple Git-113)
>> 
>> 
>> 
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Thanks
Steven