This can be extended easily to skip the buffer growing for codecs which do
not need it.
Signed-off-by: Michael Niedermayer <michae...@gmx.at>
---
libavcodec/avcodec.h | 8 +++++++-
libavcodec/utils.c | 12 ++++++++++--
2 files changed, 17 insertions(+), 3 deletions(-)
diff --git a/libavcodec/avcodec.h b/libavcodec/avcodec.h
index 99467bb..ec95194 100644
--- a/libavcodec/avcodec.h
+++ b/libavcodec/avcodec.h
@@ -4128,9 +4128,15 @@ int avcodec_decode_audio4(AVCodecContext *avctx, AVFrame
*frame,
* Some decoders may support multiple frames in a single AVPacket, such
* decoders would then just decode the first frame.
*
- * @warning The input buffer must be FF_INPUT_BUFFER_PADDING_SIZE larger than
+ * @warning If you use non AVBuffer based AVPackets, then the input buffer must
+ * be FF_INPUT_BUFFER_PADDING_SIZE larger than
* the actual read bytes because some optimized bitstream readers read 32 or 64
* bits at once and could read over the end.
+ * If you do use AVBuffer based AVPackets and the allocated space as indicated
+ * by the AVBuffer does not include FF_INPUT_BUFFER_PADDING_SIZE padding then
+ * many decoders will reallocate the buffer.
+ * Most AVPacket as created by the FFmpeg APIs will already include the needed
+ * padding.
*
* @warning The end of the input buffer buf should be set to 0 to ensure that
* no overreading happens for damaged MPEG streams.
diff --git a/libavcodec/utils.c b/libavcodec/utils.c
index 1ec5cae..eaa0431 100644
--- a/libavcodec/utils.c
+++ b/libavcodec/utils.c
@@ -2332,7 +2332,8 @@ int attribute_align_arg
avcodec_decode_video2(AVCodecContext *avctx, AVFrame *pi
AVCodecInternal *avci = avctx->internal;
int ret;
// copy to ensure we do not change avpkt
- AVPacket tmp = *avpkt;
+ AVPacket tmp;
+ int did_split = 0;
if (!avctx->codec)
return AVERROR(EINVAL);
@@ -2347,8 +2348,15 @@ int attribute_align_arg
avcodec_decode_video2(AVCodecContext *avctx, AVFrame *pi
av_frame_unref(picture);
+ if (avpkt->buf && avpkt->size && avpkt->buf->size - avpkt->size <
FF_INPUT_BUFFER_PADDING_SIZE) {
+ if ((ret = av_grow_packet(avpkt, FF_INPUT_BUFFER_PADDING_SIZE)) < 0)
+ goto fail;
+ tmp.size -= FF_INPUT_BUFFER_PADDING_SIZE;
+ }
+ tmp = *avpkt;
+
if ((avctx->codec->capabilities & CODEC_CAP_DELAY) || avpkt->size ||
(avctx->active_thread_type & FF_THREAD_FRAME)) {
- int did_split = av_packet_split_side_data(&tmp);
+ did_split = av_packet_split_side_data(&tmp);
ret = apply_param_change(avctx, &tmp);
if (ret < 0) {
av_log(avctx, AV_LOG_ERROR, "Error applying parameter changes.\n");
--
1.7.9.5
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