@@ -1935,6 +1935,10 @@ parameter @var{text}.

 If both @var{text} and @var{textfile} are specified, an error is thrown.

+@item reload

+If set to 1, the @var{textfile} will be reloaded before each frame.

+Be sure to update it atomically, or it may be read partially, or even fail.

+

 @item x, y

 The expressions which specify the offsets where text will be drawn

 within the video frame. They are relative to the top/left border of the

@@ -167,6 +167,7 @@ typedef struct {

     AVTimecode  tc;                 ///< timecode context

     int tc24hmax;                   ///< 1 if timecode is wrapped to 24 hours, 0 otherwise

     int frame_id;

+    int reload;                     ///< reload text file for each frame

 } DrawTextContext;

 #define OFFSET(x) offsetof(DrawTextContext, x)

@@ -199,6 +200,7 @@ static const AVOption drawtext_options[]= {

 {"timecode_rate", "set rate (timecode only)", OFFSET(tc_rate),   AV_OPT_TYPE_RATIONAL, {.dbl=0},          0,  INT_MAX, FLAGS},

 {"r",        "set rate (timecode only)", OFFSET(tc_rate),        AV_OPT_TYPE_RATIONAL, {.dbl=0},          0,  INT_MAX, FLAGS},

 {"rate",     "set rate (timecode only)", OFFSET(tc_rate),        AV_OPT_TYPE_RATIONAL, {.dbl=0},          0,  INT_MAX, FLAGS},

+{"reload",   "reload text file for each frame", OFFSET(reload),  AV_OPT_TYPE_INT,    {.i64=0},            0,        1, FLAGS},

 {"fix_bounds", "if true, check and fix text coords to avoid clipping", OFFSET(fix_bounds), AV_OPT_TYPE_INT, {.i64=1}, 0, 1, FLAGS},

 /* FT_LOAD_* flags */

@@ -393,6 +395,29 @@ static int load_font(AVFilterContext *ctx)

     return err;

 }

+static int load_textfile(AVFilterContext *ctx)

+{

+    DrawTextContext *dtext = ctx->priv;

+    int err;

+    uint8_t *textbuf;

+    size_t textbuf_size;

+

+    if ((err = av_file_map(dtext->textfile, &textbuf, &textbuf_size, 0, ctx)) < 0) {

+        av_log(ctx, AV_LOG_ERROR,

+               "The text file '%s' could not be read or is empty\n",

+               dtext->textfile);

+        return err;

+    }

+

+    if (!(dtext->text = av_realloc(dtext->text, textbuf_size + 1)))

+        return AVERROR(ENOMEM);

+    memcpy(dtext->text, textbuf, textbuf_size);

+    dtext->text[textbuf_size] = 0;

+    av_file_unmap(textbuf, textbuf_size);

+

+    return 0;

+}

+

 static av_cold int init(AVFilterContext *ctx, const char *args)

 {

     int err;

@@ -411,28 +436,18 @@ static av_cold int init(AVFilterContext *ctx, const char *args)

     }

     if (dtext->textfile) {

-        uint8_t *textbuf;

-        size_t textbuf_size;

-

         if (dtext->text) {

             av_log(ctx, AV_LOG_ERROR,

                    "Both text and text file provided. Please provide only one\n");

             return AVERROR(EINVAL);

         }

-        if ((err = av_file_map(dtext->textfile, &textbuf, &textbuf_size, 0, ctx)) < 0) {

-            av_log(ctx, AV_LOG_ERROR,

-                   "The text file '%s' could not be read or is empty\n",

-                   dtext->textfile);

+        if ((err = load_textfile(ctx)) < 0)

             return err;

-        }

-

-        if (!(dtext->text = av_malloc(textbuf_size+1)))

-            return AVERROR(ENOMEM);

-        memcpy(dtext->text, textbuf, textbuf_size);

-        dtext->text[textbuf_size] = 0;

-        av_file_unmap(textbuf, textbuf_size);

     }

+    if (dtext->reload && !dtext->textfile)

+        av_log(ctx, AV_LOG_WARNING, "No file to reload\n");

+

     if (dtext->tc_opt_string) {

         int ret = av_timecode_init_from_string(&dtext->tc, dtext->tc_rate,

                                                dtext->tc_opt_string, ctx);

@@ -972,6 +987,10 @@ static int filter_frame(AVFilterLink *inlink, AVFilterBufferRef *frame)

     DrawTextContext *dtext = ctx->priv;

     int ret;

+    if (dtext->reload)

+        if ((ret = load_textfile(ctx)) < 0)

+            return ret;

+

     dtext->var_values[VAR_T] = frame->pts == AV_NOPTS_VALUE ?

         NAN : frame->pts * av_q2d(inlink->time_base);