[FFmpeg-cvslog] avfilter/vf_subtitles: Fix leaks on failure

[Andreas Rheinhardt]

ffmpeg | branch: master | Andreas Rheinhardt <andreas.rheinhardt at gmail.com> | Thu Sep 10 21:39:28 2020 +0200| [77ace1ffea6bd40d44326c1a87a55db0937877f1] | committer: Andreas Rheinhardt

avfilter/vf_subtitles: Fix leaks on failure

init_subtitles() sometimes returned directly upon error without cleaning
up after itself. The easiest way to trigger this is by using
picture-based subtitles; it is also possible to run into this in case of
missing decoders or allocation failures.

Furthermore, return the proper error code in case of missing decoder.

Reviewed-by: Nicolas George <george at nsup.org>
Reviewed-by: Paul B Mahol <onemda at gmail.com>
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt at gmail.com>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=77ace1ffea6bd40d44326c1a87a55db0937877f1
---

 libavfilter/vf_subtitles.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/libavfilter/vf_subtitles.c b/libavfilter/vf_subtitles.c
index 1bd42391e0..2d3145bf2d 100644
--- a/libavfilter/vf_subtitles.c
+++ b/libavfilter/vf_subtitles.c
@@ -384,13 +384,15 @@ static av_cold int init_subtitles(AVFilterContext *ctx)
     if (!dec) {
         av_log(ctx, AV_LOG_ERROR, "Failed to find subtitle codec %s\n",
                avcodec_get_name(st->codecpar->codec_id));
-        return AVERROR(EINVAL);
+        ret = AVERROR_DECODER_NOT_FOUND;
+        goto end;
     }
     dec_desc = avcodec_descriptor_get(st->codecpar->codec_id);
     if (dec_desc && !(dec_desc->props & AV_CODEC_PROP_TEXT_SUB)) {
         av_log(ctx, AV_LOG_ERROR,
                "Only text based subtitles are currently supported\n");
-        return AVERROR_PATCHWELCOME;
+        ret = AVERROR_PATCHWELCOME;
+        goto end;
     }
     if (ass->charenc)
         av_dict_set(&codec_opts, "sub_charenc", ass->charenc, 0);
@@ -398,8 +400,10 @@ static av_cold int init_subtitles(AVFilterContext *ctx)
         av_dict_set(&codec_opts, "sub_text_format", "ass", 0);
 
     dec_ctx = avcodec_alloc_context3(dec);
-    if (!dec_ctx)
-        return AVERROR(ENOMEM);
+    if (!dec_ctx) {
+        ret = AVERROR(ENOMEM);
+        goto end;
+    }
 
     ret = avcodec_parameters_to_context(dec_ctx, st->codecpar);
     if (ret < 0)