On Friday 01 August 2014 10:04:17 am Clément Bœsch wrote:
> On Fri, Aug 01, 2014 at 01:54:57AM +0200, Carl Eugen Hoyos wrote:
> > When transcoding an input file with subtitles to mkv, ffmpeg by default
> > tries to encode the subtitles even if the input contains bitmap
> > subtitles. Attached patch should fix this issue reported in ticket #3819
> > (and before iirc).
> > This patch currently does not work correctly for teletext input streams
> > because no properties are defined for teletext, I suspect it should be
> > (AV_CODEC_PROP_TEXT_SUB | AV_CODEC_PROP_BITMAP_SUB). In any case, this
> > corner-case should not affect this patch imo.
I worked around this by automatically mapping subtitles if no properties
are set.
> > + if (subtitle_codec_name ||
> > +
> > avcodec_find_encoder(oc->oformat->subtitle_codec) && +
> >
> > avcodec_descriptor_get(avcodec_find_encoder(oc->oformat->subtitle_codec)-
> >>id) && +
> > avcodec_descriptor_get(input_streams[i]->st->codec->codec_id) && +
> >
> > avcodec_descriptor_get(avcodec_find_encoder(oc->oformat->subtitle_codec)-
> >>id)->props & +
> > avcodec_descriptor_get(input_streams[i]->st->codec->codec_id)->props &
>
> You have a scope opened here, please use 2 intermediate const to store the
> 2 descriptor pointers, because it's currently unreadable.
Slightly more readable version attached.
>
> > + (AV_CODEC_PROP_TEXT_SUB |
> > AV_CODEC_PROP_BITMAP_SUB)) { +
> > new_subtitle_stream(o, oc, i);
> > + break;
> > + }
>
> BTW, do we have an obvious warning nowadays if someone tries to map a
> bitmap sub to a text one?
I believe the warning is the reason for ticket #3819.
In any case, this is orthoganal to this patch imo: The patch tries
to cover automatic subtitle mapping (in the useless case), iiuc
you (also) mean the case when a user specifies a subtitle encoder
that will not work.
Thank you, Carl Eugen
diff --git a/ffmpeg_opt.c b/ffmpeg_opt.c
index 9604a6a..1962cf4 100644
--- a/ffmpeg_opt.c
+++ b/ffmpeg_opt.c
@@ -1870,8 +1870,27 @@ static int open_output_file(OptionsContext *o, const
char *filename)
if (!o->subtitle_disable &&
(avcodec_find_encoder(oc->oformat->subtitle_codec) || subtitle_codec_name)) {
for (i = 0; i < nb_input_streams; i++)
if (input_streams[i]->st->codec->codec_type ==
AVMEDIA_TYPE_SUBTITLE) {
- new_subtitle_stream(o, oc, i);
- break;
+ AVCodecDescriptor const *input_descriptor =
+
avcodec_descriptor_get(input_streams[i]->st->codec->codec_id);
+ AVCodecDescriptor const *output_descriptor = NULL;
+ AVCodec const *output_codec =
+ avcodec_find_encoder(oc->oformat->subtitle_codec);
+ int input_props = 0, output_props = 0;
+ if (output_codec)
+ output_descriptor =
avcodec_descriptor_get(output_codec->id);
+ if (input_descriptor)
+ input_props = input_descriptor->props &
(AV_CODEC_PROP_TEXT_SUB | AV_CODEC_PROP_BITMAP_SUB);
+ if (output_descriptor)
+ output_props = output_descriptor->props &
(AV_CODEC_PROP_TEXT_SUB | AV_CODEC_PROP_BITMAP_SUB);
+ if (subtitle_codec_name ||
+ input_props & output_props ||
+ // Map dvb teletext which has neither property to any
output subtitle encoder
+ input_descriptor && output_descriptor &&
+ (!input_descriptor->props ||
+ !output_descriptor->props)) {
+ new_subtitle_stream(o, oc, i);
+ break;
+ }
}
}
/* do something with data? */
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