This can be extended easily to skip the buffer growing for codecs which do
not need it.
The added field or a equivalent change is needed as the AVBuffer
size might not match the actually allocated and saftely accessable
memory
Signed-off-by: Michael Niedermayer <michae...@gmx.at>
---
libavcodec/avcodec.h | 16 ++++++++++++++++
libavcodec/utils.c | 19 ++++++++++++++++++-
2 files changed, 34 insertions(+), 1 deletion(-)
diff --git a/libavcodec/avcodec.h b/libavcodec/avcodec.h
index 99467bb..ed0bee0 100644
--- a/libavcodec/avcodec.h
+++ b/libavcodec/avcodec.h
@@ -3128,6 +3128,18 @@ typedef struct AVCodecContext {
* - decoding: set by user through AVOPtions (NO direct access)
*/
char *codec_whitelist;
+
+ /**
+ * Allocated input size
+ * If this is 0 then it is assumed the user allocated size +
FF_INPUT_BUFFER_PADDING_SIZE.
+ * Note, many decoders need the padding and will copy/reallocate the buffer
+ * if insufficient padding is provided.
+ * Currently only supported for video.
+ * This also requires the
+ * - encoding: unused
+ * - decoding: set by user, user must access through
av_codec_set_allocated_input_size() (NO direct access)
+ */
+ int allocated_input_size;
} AVCodecContext;
AVRational av_codec_get_pkt_timebase (const AVCodecContext *avctx);
@@ -3145,6 +3157,9 @@ void av_codec_set_seek_preroll(AVCodecContext *avctx, int
val);
uint16_t *av_codec_get_chroma_intra_matrix(const AVCodecContext *avctx);
void av_codec_set_chroma_intra_matrix(AVCodecContext *avctx, uint16_t *val);
+int av_codec_get_allocated_input_size(const AVCodecContext *avctx);
+void av_codec_set_allocated_input_size(AVCodecContext *avctx, int val);
+
/**
* AVProfile.
*/
@@ -4131,6 +4146,7 @@ int avcodec_decode_audio4(AVCodecContext *avctx, AVFrame
*frame,
* @warning 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.
+ * Also @see allocated_input_size.
*
* @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..e835b83 100644
--- a/libavcodec/utils.c
+++ b/libavcodec/utils.c
@@ -1274,6 +1274,7 @@ MAKE_ACCESSORS(AVCodecContext, codec, const
AVCodecDescriptor *, codec_descripto
MAKE_ACCESSORS(AVCodecContext, codec, int, lowres)
MAKE_ACCESSORS(AVCodecContext, codec, int, seek_preroll)
MAKE_ACCESSORS(AVCodecContext, codec, uint16_t*, chroma_intra_matrix)
+MAKE_ACCESSORS(AVCodecContext, codec, int, allocated_input_size)
int av_codec_get_max_lowres(const AVCodec *codec)
{
@@ -2333,6 +2334,9 @@ int attribute_align_arg
avcodec_decode_video2(AVCodecContext *avctx, AVFrame *pi
int ret;
// copy to ensure we do not change avpkt
AVPacket tmp = *avpkt;
+ int did_split = 0;
+ int needs_copy = avctx->allocated_input_size && avpkt->size &&
+ avctx->allocated_input_size - avpkt->size <
FF_INPUT_BUFFER_PADDING_SIZE;
if (!avctx->codec)
return AVERROR(EINVAL);
@@ -2347,8 +2351,19 @@ int attribute_align_arg
avcodec_decode_video2(AVCodecContext *avctx, AVFrame *pi
av_frame_unref(picture);
+ if (needs_copy) {
+ memset(&tmp, 0, sizeof(tmp));
+ if ((ret = av_packet_ref(&tmp, avpkt)) < 0) {
+ needs_copy = 0;
+ goto fail;
+ }
+ if ((ret = av_grow_packet(&tmp, FF_INPUT_BUFFER_PADDING_SIZE)) < 0)
+ goto fail;
+ tmp.size -= FF_INPUT_BUFFER_PADDING_SIZE;
+ }
+
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");
@@ -2388,6 +2403,8 @@ fail:
if(ret == tmp.size)
ret = avpkt->size;
}
+ if (needs_copy)
+ av_packet_unref(&tmp);
if (*got_picture_ptr) {
if (!avctx->refcounted_frames) {
--
1.7.9.5
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