James Almer:
> Keeping only the latest packet fed to the decoder works only for decoders that
> return a frame immediately after every consumed packet. Decoders that consume
> several packets before they return a frame will fill said frame with
> properties
> taken from the last consumed packet instead of the earliest.
>
> Signed-off-by: James Almer <jamr...@gmail.com>
> ---
> This essentially enables decoders implementing the AVCodec.receive_frame API
> to
> not require having to deal with timestamps and such properties internally, and
> letting ff_decode_frame_props() do all the work instead (See libdav1d, which
> i'll adapt once this goes in).
>
> As an example, this fixes the timestamps for the audio track in
> bink/binkaudio_rdft.bik from the FATE suite, where the decoder wrongly assumed
> ff_decode_frame_props() alone would handle them right.
> The reason the relevant fate test is unaffected is because it just compares
> the
> decoded output with a reference pcm file.
>
> Haven't looked too much into it, but i assume this change could simplify some
> AV_CODEC_CAP_DELAY decoders that keep track of timestamps, even those using
> the
> old AVCodec.decode() API.
>
> libavcodec/decode.c | 34 +++++++++++++++++++++++++---------
> libavcodec/internal.h | 2 ++
> libavcodec/utils.c | 3 +++
> 3 files changed, 30 insertions(+), 9 deletions(-)
>
> diff --git a/libavcodec/decode.c b/libavcodec/decode.c
> index da587ac1f6..de36e28d3c 100644
> --- a/libavcodec/decode.c
> +++ b/libavcodec/decode.c
> @@ -43,6 +43,7 @@
> #include "decode.h"
> #include "hwconfig.h"
> #include "internal.h"
> +#include "packet_internal.h"
> #include "thread.h"
>
> typedef struct FramePool {
> @@ -142,15 +143,22 @@ fail2:
> return 0;
> }
>
> -static int extract_packet_props(AVCodecInternal *avci, const AVPacket *pkt)
> +#define IS_EMPTY(pkt) (!(pkt)->data && !(pkt)->side_data_elems)
> +
> +static int extract_packet_props(AVCodecInternal *avci, AVPacket *pkt)
> {
> int ret = 0;
>
> - av_packet_unref(avci->last_pkt_props);
> - if (pkt) {
> - ret = av_packet_copy_props(avci->last_pkt_props, pkt);
> - if (!ret)
> - avci->last_pkt_props->size = pkt->size; // HACK: Needed for
> ff_decode_frame_props().
> + ret = avpriv_packet_list_put(&avci->pkt_props, &avci->pkt_props_tail,
> pkt,
> + FF_PACKETLIST_FLAG_REF_PACKET);
> + if (ret < 0)
> + return ret;
> +
> + if (IS_EMPTY(avci->last_pkt_props)) {
> + ret = avpriv_packet_list_get(&avci->pkt_props,
> + &avci->pkt_props_tail,
> + avci->last_pkt_props);
> + av_assert0(ret != AVERROR(EAGAIN));
> }
> return ret;
> }
> @@ -512,6 +520,7 @@ FF_ENABLE_DEPRECATION_WARNINGS
>
> if (ret >= pkt->size || ret < 0) {
> av_packet_unref(pkt);
> + av_packet_unref(avci->last_pkt_props);
> } else {
> int consumed = ret;
>
> @@ -550,9 +559,11 @@ static int decode_receive_frame_internal(AVCodecContext
> *avctx, AVFrame *frame)
>
> av_assert0(!frame->buf[0]);
>
> - if (avctx->codec->receive_frame)
> + if (avctx->codec->receive_frame) {
> ret = avctx->codec->receive_frame(avctx, frame);
> - else
> + if (ret != AVERROR(EAGAIN))
> + av_packet_unref(avci->last_pkt_props);
> + } else
> ret = decode_simple_receive_frame(avctx, frame);
>
> if (ret == AVERROR_EOF)
> @@ -1683,7 +1694,7 @@ static int add_metadata_from_side_data(const AVPacket
> *avpkt, AVFrame *frame)
>
> int ff_decode_frame_props(AVCodecContext *avctx, AVFrame *frame)
> {
> - const AVPacket *pkt = avctx->internal->last_pkt_props;
> + AVPacket *pkt = avctx->internal->last_pkt_props;
> int i;
> static const struct {
> enum AVPacketSideDataType packet;
> @@ -1701,6 +1712,11 @@ int ff_decode_frame_props(AVCodecContext *avctx,
> AVFrame *frame)
> { AV_PKT_DATA_S12M_TIMECODE,
> AV_FRAME_DATA_S12M_TIMECODE },
> };
>
> + if (IS_EMPTY(pkt))
> + avpriv_packet_list_get(&avctx->internal->pkt_props,
> + &avctx->internal->pkt_props_tail,
> + pkt);
> +
The check below indicates that pkt might be NULL, yet IS_EMPTY(pkt)
already dereferences it.
> if (pkt) {
> frame->pts = pkt->pts;
> #if FF_API_PKT_PTS
> diff --git a/libavcodec/internal.h b/libavcodec/internal.h
> index 5d0e6e7831..ce4dbbc2b9 100644
> --- a/libavcodec/internal.h
> +++ b/libavcodec/internal.h
> @@ -145,6 +145,8 @@ typedef struct AVCodecInternal {
> * for decoding.
> */
> AVPacket *last_pkt_props;
> + AVPacketList *pkt_props;
> + AVPacketList *pkt_props_tail;
>
> /**
> * temporary buffer used for encoders to store their bitstream
> diff --git a/libavcodec/utils.c b/libavcodec/utils.c
> index 14cb5cf1aa..4a180a1500 100644
> --- a/libavcodec/utils.c
> +++ b/libavcodec/utils.c
> @@ -50,6 +50,7 @@
> #include "thread.h"
> #include "frame_thread_encoder.h"
> #include "internal.h"
> +#include "packet_internal.h"
> #include "put_bits.h"
> #include "raw.h"
> #include "bytestream.h"
> @@ -1149,6 +1150,8 @@ av_cold int avcodec_close(AVCodecContext *avctx)
> av_packet_free(&avctx->internal->compat_encode_packet);
> av_packet_free(&avctx->internal->buffer_pkt);
> av_packet_free(&avctx->internal->last_pkt_props);
> + avpriv_packet_list_free(&avctx->internal->pkt_props,
> + &avctx->internal->pkt_props_tail);
>
> av_packet_free(&avctx->internal->ds.in_pkt);
> av_frame_free(&avctx->internal->es.in_frame);
>
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