From: Jiejun Zhang <zhangjiejun1...@gmail.com> 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. --- libavcodec/audiotoolboxenc.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/libavcodec/audiotoolboxenc.c b/libavcodec/audiotoolboxenc.c index 71885d1530..4d8130af96 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 +482,12 @@ 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); + if ((ret = av_frame_ref(at->encoding_frame, frame)) < 0) { + *nb_packets = 0; + return ret; + } + ff_bufqueue_add(avctx, &at->used_frame_queue, frame); return 0; @@ -565,6 +578,7 @@ 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; } -- 2.14.3 (Apple Git-98) _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel