From 7dd44cde2abb156710f26a08b6cd6c8dd9a9793d Mon Sep 17 00:00:00 2001
From: wm4 <nfxjfg@googlemail.com>
Date: Thu, 2 Mar 2017 16:01:01 +0100
Subject: [PATCH] ffmpeg: delay processing of subtitles before filters are
initialized
If a subtitle packet came before the first video frame could be fully
decoded, the subtitle packet would get discarded. This puts the subtitle
into a queue instead, and processes it once the attached filter graph is
initialized.
---
ffmpeg.c | 31 ++++++++++++++++++++++++++++---
ffmpeg.h | 3 +++
ffmpeg_filter.c | 13 +++++++++++++
3 files changed, 44 insertions(+), 3 deletions(-)
diff --git a/ffmpeg.c b/ffmpeg.c
index 6e57524558e..db7e8cd0c67 100644
--- a/ffmpeg.c
+++ b/ffmpeg.c
@@ -226,7 +226,7 @@ static void sub2video_push_ref(InputStream *ist, int64_t pts)
AV_BUFFERSRC_FLAG_PUSH);
}
-static void sub2video_update(InputStream *ist, AVSubtitle *sub)
+void sub2video_update(InputStream *ist, AVSubtitle *sub)
{
AVFrame *frame = ist->sub2video.frame;
int8_t *dst;
@@ -480,6 +480,15 @@ static void ffmpeg_cleanup(int ret)
av_frame_free(&frame);
}
av_fifo_free(fg->inputs[j]->frame_queue);
+ if (fg->inputs[j]->ist->sub2video.sub_queue) {
+ while (av_fifo_size(fg->inputs[j]->ist->sub2video.sub_queue)) {
+ AVSubtitle sub;
+ av_fifo_generic_read(fg->inputs[j]->ist->sub2video.sub_queue,
+ &sub, sizeof(sub), NULL);
+ avsubtitle_free(&sub);
+ }
+ av_fifo_free(fg->inputs[j]->ist->sub2video.sub_queue);
+ }
av_buffer_unref(&fg->inputs[j]->hw_frames_ctx);
av_freep(&fg->inputs[j]->name);
av_freep(&fg->inputs[j]);
@@ -2468,6 +2477,7 @@ fail:
static int transcode_subtitles(InputStream *ist, AVPacket *pkt, int *got_output)
{
AVSubtitle subtitle;
+ int free_sub = 1;
int i, ret = avcodec_decode_subtitle2(ist->dec_ctx,
&subtitle, got_output, pkt);
@@ -2502,7 +2512,21 @@ static int transcode_subtitles(InputStream *ist, AVPacket *pkt, int *got_output)
if (!*got_output)
return ret;
- sub2video_update(ist, &subtitle);
+ if (ist->sub2video.frame) {
+ sub2video_update(ist, &subtitle);
+ } else if (ist->nb_filters) {
+ if (!ist->sub2video.sub_queue)
+ ist->sub2video.sub_queue = av_fifo_alloc(8 * sizeof(AVSubtitle));
+ if (!ist->sub2video.sub_queue)
+ exit_program(1);
+ if (!av_fifo_space(ist->sub2video.sub_queue)) {
+ ret = av_fifo_realloc2(ist->sub2video.sub_queue, 2 * av_fifo_size(ist->sub2video.sub_queue));
+ if (ret < 0)
+ exit_program(1);
+ }
+ av_fifo_generic_write(ist->sub2video.sub_queue, &subtitle, sizeof(subtitle), NULL);
+ free_sub = 0;
+ }
if (!subtitle.num_rects)
goto out;
@@ -2520,7 +2544,8 @@ static int transcode_subtitles(InputStream *ist, AVPacket *pkt, int *got_output)
}
out:
- avsubtitle_free(&subtitle);
+ if (free_sub)
+ avsubtitle_free(&subtitle);
return ret;
}
diff --git a/ffmpeg.h b/ffmpeg.h
index 59f6cb36596..06a12511248 100644
--- a/ffmpeg.h
+++ b/ffmpeg.h
@@ -337,6 +337,7 @@ typedef struct InputStream {
struct sub2video {
int64_t last_pts;
int64_t end_pts;
+ AVFifoBuffer *sub_queue; ///< queue of AVSubtitle* before filter init
AVFrame *frame;
int w, h;
} sub2video;
@@ -636,6 +637,8 @@ int filtergraph_is_simple(FilterGraph *fg);
int init_simple_filtergraph(InputStream *ist, OutputStream *ost);
int init_complex_filtergraph(FilterGraph *fg);
+void sub2video_update(InputStream *ist, AVSubtitle *sub);
+
int ifilter_parameters_from_frame(InputFilter *ifilter, const AVFrame *frame);
int ffmpeg_parse_options(int argc, char **argv);
diff --git a/ffmpeg_filter.c b/ffmpeg_filter.c
index 816c906c7e7..da2a46d3b71 100644
--- a/ffmpeg_filter.c
+++ b/ffmpeg_filter.c
@@ -1137,6 +1137,19 @@ int configure_filtergraph(FilterGraph *fg)
}
}
+ /* process queued up subtitle packets */
+ for (i = 0; i < fg->nb_inputs; i++) {
+ InputStream *ist = fg->inputs[i]->ist;
+ if (ist->sub2video.sub_queue && ist->sub2video.frame) {
+ while (av_fifo_size(ist->sub2video.sub_queue)) {
+ AVSubtitle tmp;
+ av_fifo_generic_read(ist->sub2video.sub_queue, &tmp, sizeof(tmp), NULL);
+ sub2video_update(ist, &tmp);
+ avsubtitle_free(&tmp);
+ }
+ }
+ }
+
return 0;
}
--
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