From 677701c6b319d2d3b95a27179fde6ec2a863bf72 Mon Sep 17 00:00:00 2001 From: Jiejun Zhang Date: Wed, 3 Jan 2018 12:54:20 +0800 Subject: lavc/audiotoolboxenc: fix noise in encoded audio This fixes #6940 Although undocumented, AudioToolbox seems to require the data supplied by the callback (i.e. ffat_encode_callback) being unchanged until the next time the callback is called. In the old implementation, the AVBuffer backing the frame is recycled after the frame is freed, and somebody else (maybe the decoder) will write into the AVBuffer and change the data. AudioToolbox then encodes some wrong data and noise is produced. Retaining a frame reference solves this problem. Signed-off-by: James Almer --- libavcodec/audiotoolboxenc.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+) (limited to 'libavcodec') diff --git a/libavcodec/audiotoolboxenc.c b/libavcodec/audiotoolboxenc.c index 71885d1..2c18916 100644 --- a/libavcodec/audiotoolboxenc.c +++ b/libavcodec/audiotoolboxenc.c @@ -48,6 +48,8 @@ typedef struct ATDecodeContext { AudioFrameQueue afq; int eof; int frame_size; + + AVFrame* encoding_frame; } ATDecodeContext; static UInt32 ffat_get_format_id(enum AVCodecID codec, int profile) @@ -442,6 +444,10 @@ static av_cold int ffat_init_encoder(AVCodecContext *avctx) ff_af_queue_init(avctx, &at->afq); + at->encoding_frame = av_frame_alloc(); + if (!at->encoding_frame) + return AVERROR(ENOMEM); + return 0; } @@ -453,6 +459,7 @@ static OSStatus ffat_encode_callback(AudioConverterRef converter, UInt32 *nb_pac AVCodecContext *avctx = inctx; ATDecodeContext *at = avctx->priv_data; AVFrame *frame; + int ret; if (!at->frame_queue.available) { if (at->eof) { @@ -475,6 +482,13 @@ static OSStatus ffat_encode_callback(AudioConverterRef converter, UInt32 *nb_pac if (*nb_packets > frame->nb_samples) *nb_packets = frame->nb_samples; + av_frame_unref(at->encoding_frame); + ret = av_frame_ref(at->encoding_frame, frame); + if (ret < 0) { + *nb_packets = 0; + return ret; + } + ff_bufqueue_add(avctx, &at->used_frame_queue, frame); return 0; @@ -565,6 +579,7 @@ static av_cold int ffat_close_encoder(AVCodecContext *avctx) ff_bufqueue_discard_all(&at->frame_queue); ff_bufqueue_discard_all(&at->used_frame_queue); ff_af_queue_close(&at->afq); + av_frame_free(&at->encoding_frame); return 0; } -- cgit v1.1