From: Matthieu Bouron <[email protected]>
Avoid decoding a frame to get the codec parameters while the codec
supports FF_CODEC_CAP_SKIP_FRAME_FILL_PARAM. This is particulary useful
to avoid decoding twice images (once in avformat_find_stream_info and
once when the actual decode is made).
---
libavformat/utils.c | 12 ++++++++++++
1 file changed, 12 insertions(+)
diff --git a/libavformat/utils.c b/libavformat/utils.c
index 5c4d452..ba62f2b 100644
--- a/libavformat/utils.c
+++ b/libavformat/utils.c
@@ -2695,6 +2695,8 @@ static int try_decode_frame(AVFormatContext *s, AVStream
*st, AVPacket *avpkt,
AVFrame *frame = av_frame_alloc();
AVSubtitle subtitle;
AVPacket pkt = *avpkt;
+ int do_skip_frame = 0;
+ enum AVDiscard skip_frame;
if (!frame)
return AVERROR(ENOMEM);
@@ -2733,6 +2735,12 @@ static int try_decode_frame(AVFormatContext *s, AVStream
*st, AVPacket *avpkt,
goto fail;
}
+ if (st->codec->codec->caps_internal & FF_CODEC_CAP_SKIP_FRAME_FILL_PARAM) {
+ do_skip_frame = 1;
+ skip_frame = st->codec->skip_frame;
+ st->codec->skip_frame = AVDISCARD_ALL;
+ }
+
while ((pkt.size > 0 || (!pkt.data && got_picture)) &&
ret >= 0 &&
(!has_codec_parameters(st, NULL) ||
!has_decode_delay_been_guessed(st) ||
@@ -2768,6 +2776,10 @@ static int try_decode_frame(AVFormatContext *s, AVStream
*st, AVPacket *avpkt,
ret = -1;
fail:
+ if (do_skip_frame) {
+ st->codec->skip_frame = skip_frame;
+ }
+
av_frame_free(&frame);
return ret;
}
--
2.6.2
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