From: Jyrki Vesterinen <[email protected]>
If a developer using FFmpeg libraries seeks into an earlier position and calls
avcodec_flush_buffers() afterwards as recommended, the Vorbis decoder will drop
the next frame, since buffer flushing clears the first_frame flag. As a result,
the audio samples the calling code receives may be ahead of the requested seek
position, which is unacceptable in some use cases such as playing a looping
sound effect.
This commit removes the first_frame flag entirely and instead uses the
presentation timestamp to determine if it's the first frame.
---
libavcodec/vorbisdec.c | 5 +----
1 file changed, 1 insertion(+), 4 deletions(-)
diff --git a/libavcodec/vorbisdec.c b/libavcodec/vorbisdec.c
index 4d03947c49..d4b030d7b9 100644
--- a/libavcodec/vorbisdec.c
+++ b/libavcodec/vorbisdec.c
@@ -130,7 +130,6 @@ typedef struct vorbis_context_s {
AVFloatDSPContext *fdsp;
FFTContext mdct[2];
- uint8_t first_frame;
uint32_t version;
uint8_t audio_channels;
uint32_t audio_samplerate;
@@ -1845,8 +1844,7 @@ static int vorbis_decode_frame(AVCodecContext *avctx,
AVFrame *frame,
if ((len = vorbis_parse_audio_packet(vc, channel_ptrs)) <= 0)
return len;
- if (!vc->first_frame) {
- vc->first_frame = 1;
+ if (frame->pts < 0) {
*got_frame_ptr = 0;
av_frame_unref(frame);
return buf_size;
@@ -1881,7 +1879,6 @@ static av_cold void vorbis_decode_flush(AVCodecContext
*avctx)
sizeof(*vc->saved));
}
vc->previous_window = -1;
- vc->first_frame = 0;
}
const FFCodec ff_vorbis_decoder = {
--
2.37.2.windows.2
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