[FFmpeg-devel] [PATCH] lavfi: add subtitles filter.
Clément Bœsch
ubitux at gmail.com
Thu Nov 29 03:33:01 CET 2012
TODO: lavfi micro bump
TODO: Changelog
---
Yes I know, you guys would prefer that we add lavfi subtitles support instead.
Unfortunately, I don't see this in a near future. And on the other hand, this
is quite handy for users who just want to hardsub a .SRT file. And we can also
ffplay ... -vf subtitles=sub.srt to watch a movie with external text subtitles
after this patch.
---
configure | 1 +
doc/filters.texi | 72 ++++++++++++-----------
libavfilter/Makefile | 1 +
libavfilter/allfilters.c | 1 +
libavfilter/vf_ass.c | 146 ++++++++++++++++++++++++++++++++++++++++++-----
5 files changed, 175 insertions(+), 46 deletions(-)
diff --git a/configure b/configure
index a7990f5..6276440 100755
--- a/configure
+++ b/configure
@@ -1933,6 +1933,7 @@ aconvert_filter_deps="swresample"
amovie_filter_deps="avcodec avformat"
aresample_filter_deps="swresample"
ass_filter_deps="libass"
+subtitles_filter_deps="avformat avcodec libass"
asyncts_filter_deps="avresample"
atempo_filter_deps="avcodec rdft"
blackframe_filter_deps="gpl"
diff --git a/doc/filters.texi b/doc/filters.texi
index 0b57e03..22ce415 100644
--- a/doc/filters.texi
+++ b/doc/filters.texi
@@ -1274,38 +1274,9 @@ overlay to a video stream, consider the @var{overlay} filter instead.
@section ass
-Draw ASS (Advanced Substation Alpha) subtitles on top of input video
-using the libass library.
-
-To enable compilation of this filter you need to configure FFmpeg with
- at code{--enable-libass}.
-
-This filter accepts the following named options, expressed as a
-sequence of @var{key}=@var{value} pairs, separated by ":".
-
- at table @option
- at item filename, f
-Set the filename of the ASS file to read. It must be specified.
-
- at item original_size
-Specify the size of the original video, the video for which the ASS file
-was composed. Due to a misdesign in ASS aspect ratio arithmetic, this is
-necessary to correctly scale the fonts if the aspect ratio has been changed.
- at end table
-
-If the first key is not specified, it is assumed that the first value
-specifies the @option{filename}.
-
-For example, to render the file @file{sub.ass} on top of the input
-video, use the command:
- at example
-ass=sub.ass
- at end example
-
-which is equivalent to:
- at example
-ass=filename=sub.ass
- at end example
+Same as the @ref{subtitles} filter, except that it doesn't require libavcodec
+and libavformat to work. On the other hand, it is limited to ASS (Advanced
+Substation Alpha) subtitles files.
@section bbox
@@ -3735,6 +3706,43 @@ a pixel should be blurred or not. A value of 0 will filter all the
image, a value included in [0,30] will filter flat areas and a value
included in [-30,0] will filter edges.
+ at anchor{subtitles}
+ at section subtitles
+
+Draw subtitles subtitles on top of input video using the libass library.
+
+To enable compilation of this filter you need to configure FFmpeg with
+ at code{--enable-libass}. This filter also requires a build with libavcodec and
+libavformat to convert the passed subtitles file to ASS (Advanced Substation
+Alpha) subtitles format.
+
+This filter accepts the following named options, expressed as a
+sequence of @var{key}=@var{value} pairs, separated by ":".
+
+ at table @option
+ at item filename, f
+Set the filename of the subtitle file to read. It must be specified.
+
+ at item original_size
+Specify the size of the original video, the video for which the ASS file
+was composed. Due to a misdesign in ASS aspect ratio arithmetic, this is
+necessary to correctly scale the fonts if the aspect ratio has been changed.
+ at end table
+
+If the first key is not specified, it is assumed that the first value
+specifies the @option{filename}.
+
+For example, to render the file @file{sub.srt} on top of the input
+video, use the command:
+ at example
+subtitles=sub.srt
+ at end example
+
+which is equivalent to:
+ at example
+subtitles=filename=sub.srt
+ at end example
+
@section split
Split input video into several identical outputs.
diff --git a/libavfilter/Makefile b/libavfilter/Makefile
index 0e49912..377bd4d 100644
--- a/libavfilter/Makefile
+++ b/libavfilter/Makefile
@@ -134,6 +134,7 @@ OBJS-$(CONFIG_SETTB_FILTER) += f_settb.o
OBJS-$(CONFIG_SHOWINFO_FILTER) += vf_showinfo.o
OBJS-$(CONFIG_SMARTBLUR_FILTER) += vf_smartblur.o
OBJS-$(CONFIG_SPLIT_FILTER) += split.o
+OBJS-$(CONFIG_SUBTITLES_FILTER) += vf_ass.o
OBJS-$(CONFIG_SUPER2XSAI_FILTER) += vf_super2xsai.o
OBJS-$(CONFIG_SWAPUV_FILTER) += vf_swapuv.o
OBJS-$(CONFIG_THUMBNAIL_FILTER) += vf_thumbnail.o
diff --git a/libavfilter/allfilters.c b/libavfilter/allfilters.c
index 746e713..5a1f939 100644
--- a/libavfilter/allfilters.c
+++ b/libavfilter/allfilters.c
@@ -126,6 +126,7 @@ void avfilter_register_all(void)
REGISTER_FILTER (SHOWINFO, showinfo, vf);
REGISTER_FILTER (SMARTBLUR, smartblur, vf);
REGISTER_FILTER (SPLIT, split, vf);
+ REGISTER_FILTER (SUBTITLES, subtitles, vf);
REGISTER_FILTER (SUPER2XSAI, super2xsai, vf);
REGISTER_FILTER (SWAPUV, swapuv, vf);
REGISTER_FILTER (THUMBNAIL, thumbnail, vf);
diff --git a/libavfilter/vf_ass.c b/libavfilter/vf_ass.c
index 5f96202..dee95fa 100644
--- a/libavfilter/vf_ass.c
+++ b/libavfilter/vf_ass.c
@@ -28,6 +28,11 @@
#include <ass/ass.h>
+#include "config.h"
+#if CONFIG_SUBTITLES_FILTER
+# include "libavcodec/avcodec.h"
+# include "libavformat/avformat.h"
+#endif
#include "libavutil/avstring.h"
#include "libavutil/imgutils.h"
#include "libavutil/opt.h"
@@ -53,15 +58,13 @@ typedef struct {
#define OFFSET(x) offsetof(AssContext, x)
#define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM
-static const AVOption ass_options[] = {
+static const AVOption options[] = {
{"filename", "set the filename of the ASS file to read", OFFSET(filename), AV_OPT_TYPE_STRING, {.str = NULL}, CHAR_MIN, CHAR_MAX, FLAGS },
{"f", "set the filename of the ASS file to read", OFFSET(filename), AV_OPT_TYPE_STRING, {.str = NULL}, CHAR_MIN, CHAR_MAX, FLAGS },
{"original_size", "set the size of the original video (used to scale fonts)", OFFSET(original_w), AV_OPT_TYPE_IMAGE_SIZE, {.str = NULL}, CHAR_MIN, CHAR_MAX, FLAGS },
{NULL},
};
-AVFILTER_DEFINE_CLASS(ass);
-
/* libass supports a log level ranging from 0 to 7 */
static const int ass_libavfilter_log_level_map[] = {
AV_LOG_QUIET, /* 0 */
@@ -82,13 +85,13 @@ static void ass_log(int ass_level, const char *fmt, va_list args, void *ctx)
av_log(ctx, level, "\n");
}
-static av_cold int init(AVFilterContext *ctx, const char *args)
+static av_cold int init(AVFilterContext *ctx, const char *args, const AVClass *class)
{
AssContext *ass = ctx->priv;
static const char *shorthand[] = { "filename", NULL };
int ret;
- ass->class = &ass_class;
+ ass->class = class;
av_opt_set_defaults(ass);
if ((ret = av_opt_set_from_string(ass, args, shorthand, "=", ":")) < 0)
@@ -112,14 +115,6 @@ static av_cold int init(AVFilterContext *ctx, const char *args)
return AVERROR(EINVAL);
}
- ass->track = ass_read_file(ass->library, ass->filename, NULL);
- if (!ass->track) {
- av_log(ctx, AV_LOG_ERROR,
- "Could not create a libass track when reading file '%s'\n",
- ass->filename);
- return AVERROR(EINVAL);
- }
-
ass_set_fonts(ass->renderer, NULL, NULL, 1, NULL, 1);
return 0;
}
@@ -215,14 +210,137 @@ static const AVFilterPad ass_outputs[] = {
{ NULL }
};
+#if CONFIG_ASS_FILTER
+
+#define ass_options options
+AVFILTER_DEFINE_CLASS(ass);
+
+static av_cold int init_ass(AVFilterContext *ctx, const char *args)
+{
+ AssContext *ass = ctx->priv;
+ int ret = init(ctx, args, &ass_class);
+
+ if (ret < 0)
+ return ret;
+
+ ass->track = ass_read_file(ass->library, ass->filename, NULL);
+ if (!ass->track) {
+ av_log(ctx, AV_LOG_ERROR,
+ "Could not create a libass track when reading file '%s'\n",
+ ass->filename);
+ return AVERROR(EINVAL);
+ }
+ return 0;
+}
+
AVFilter avfilter_vf_ass = {
.name = "ass",
.description = NULL_IF_CONFIG_SMALL("Render subtitles onto input video using the libass library."),
.priv_size = sizeof(AssContext),
- .init = init,
+ .init = init_ass,
.uninit = uninit,
.query_formats = query_formats,
.inputs = ass_inputs,
.outputs = ass_outputs,
.priv_class = &ass_class,
};
+#endif
+
+#if CONFIG_SUBTITLES_FILTER
+
+#define subtitles_options options
+AVFILTER_DEFINE_CLASS(subtitles);
+
+static av_cold int init_subtitles(AVFilterContext *ctx, const char *args)
+{
+ int ret, sid;
+ AVFormatContext *fmt = NULL;
+ AVCodecContext *dec_ctx = NULL;
+ AVCodec *dec = NULL;
+ AVStream *st;
+ AVPacket pkt;
+ AssContext *ass = ctx->priv;
+
+ /* Init libass */
+ ret = init(ctx, args, &subtitles_class);
+ if (ret < 0)
+ return ret;
+ ass->track = ass_new_track(ass->library);
+ if (!ass->track) {
+ av_log(ctx, AV_LOG_ERROR, "Could not create a libass track\n");
+ return AVERROR(EINVAL);
+ }
+
+ /* Open subtitle file */
+ ret = avformat_open_input(&fmt, ass->filename, NULL, NULL);
+ if (ret < 0)
+ goto end;
+ ret = avformat_find_stream_info(fmt, NULL);
+ if (ret < 0)
+ goto end;
+
+ /* Locate subtitle stream */
+ ret = av_find_best_stream(fmt, AVMEDIA_TYPE_SUBTITLE, -1, -1, NULL, 0);
+ if (ret < 0)
+ goto end;
+ sid = ret;
+ st = fmt->streams[sid];
+
+ /* Open decoder */
+ dec_ctx = st->codec;
+ dec = avcodec_find_decoder(dec_ctx->codec_id);
+ if (!dec) {
+ av_log(NULL, AV_LOG_ERROR, "Failed to find subtitle codec\n");
+ return AVERROR(EINVAL);
+ }
+ ret = avcodec_open2(dec_ctx, dec, NULL);
+ if (ret < 0)
+ goto end;
+
+ /* Decode subtitles and push them into the renderer (libass) */
+ if (dec_ctx->subtitle_header)
+ ass_process_codec_private(ass->track,
+ dec_ctx->subtitle_header,
+ dec_ctx->subtitle_header_size);
+ av_init_packet(&pkt);
+ pkt.data = NULL;
+ pkt.size = 0;
+ while (av_read_frame(fmt, &pkt) >= 0) {
+ int i, got_subtitle;
+ AVSubtitle sub;
+
+ if (pkt.stream_index == sid) {
+ ret = avcodec_decode_subtitle2(dec_ctx, &sub, &got_subtitle, &pkt);
+ if (ret < 0 || !got_subtitle)
+ break;
+ for (i = 0; i < sub.num_rects; i++) {
+ char *ass_line = sub.rects[i]->ass;
+ ass_process_data(ass->track, ass_line, strlen(ass_line));
+ }
+ }
+ av_free_packet(&pkt);
+ avsubtitle_free(&sub);
+ }
+
+end:
+ if (fmt)
+ avformat_close_input(&fmt);
+ if (dec_ctx)
+ avcodec_close(dec_ctx);
+ if (!ret)
+ av_log(NULL, AV_LOG_INFO, "Subtitle %s loaded\n", ass->filename);
+ return ret;
+}
+
+AVFilter avfilter_vf_subtitles = {
+ .name = "subtitles",
+ .description = NULL_IF_CONFIG_SMALL("Render subtitles onto input video using the libass library."),
+ .priv_size = sizeof(AssContext),
+ .init = init_subtitles,
+ .uninit = uninit,
+ .query_formats = query_formats,
+ .inputs = ass_inputs,
+ .outputs = ass_outputs,
+ .priv_class = &subtitles_class,
+};
+#endif
--
1.8.0.1
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