[FFmpeg-devel] [PATCH v2 3/3] avcodec/cuvid: introduce a ringbuffer to reattach additional data
Clément Péron
peron.clem at gmail.com
Thu Nov 7 11:25:16 EET 2024
On Fri, 1 Nov 2024 at 18:39, Clément Péron <peron.clem at gmail.com> wrote:
>
> From: Troy Benson <t.benson-c at paravision.ai>
>
> Cuvid data packet have specific format that don't contain any side data.
> In order to keep additional information and metadata, we need to implement
> a ring buffer and reattach side data to decoded frame.
>
> Signed-off-by: Troy Benson <t.benson-c at paravision.ai>
> Signed-off-by: Clément Péron <peron.clem at gmail.com>
> ---
> libavcodec/cuviddec.c | 175 ++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 175 insertions(+)
>
> diff --git a/libavcodec/cuviddec.c b/libavcodec/cuviddec.c
> index 3fae9c12eb..464da4d2f4 100644
> --- a/libavcodec/cuviddec.c
> +++ b/libavcodec/cuviddec.c
> @@ -51,6 +51,162 @@
> #define CUVID_HAS_AV1_SUPPORT
> #endif
>
> +/// @brief Structure to store source packets.
> +/// This struct implements a circular buffer to store source packets.
> +/// The packets are packets that have already been sent to the decoder.
> +/// The reason we need the packets is because they may contain additional information and metadata,
> +/// that we need to attach to the decoded frame so that the muxers and filters can use it.
> +typedef struct sourcePkts
> +{
> + /// @brief Array of AVPackets.
> + AVPacket **pkts;
> + /// @brief Number of packets to store.
> + int capacity;
> + /// @brief Index of the first packet.
> + int start_idx;
> + /// @brief Number of packets stored. (typically we found while testing that this hovers around 8)
> + int count;
> +} sourcePkts;
> +
> +/// @brief Allocates a sourcePkts structure.
> +/// @param avctx - AVCodecContext (for logging)
> +/// @param source_pkts (output)
> +/// @param capacity - number of pkts to store
> +/// @return int = 0 on success, < 0 on error
> +int sourcePkts_alloc(AVCodecContext *avctx, sourcePkts *source_pkts, int capacity);
> +
> +/// @brief Clears the sourcePkts structure of pkts with pts less than the given pts.
> +/// @param avctx - AVCodecContext (for logging)
> +/// @param source_pkts - sourcePkts structure
> +/// @param pts - pts to clear pkts before
> +/// @return int = 0 on success, < 0 on error
> +int sourcePkts_clear(AVCodecContext *avctx, sourcePkts *source_pkts, int64_t pts);
> +
> +/// @brief Converts a logical index to a physical index.
> +/// @param source_pkts - sourcePkts structure
> +/// @param idx - logical index
> +/// @return int - physical index
> +int sourcePkts_idx(sourcePkts *source_pkts, int idx);
> +
> +/// @brief Adds a pkt to the sourcePkts structure.
> +/// @param avctx - AVCodecContext (for logging)
> +/// @param source_pkts - sourcePkts structure
> +/// @param pkt - AVPacket to add
> +/// @return int = 0 on success, < 0 on error
> +int sourcePkts_add(AVCodecContext *avctx, sourcePkts *source_pkts, AVPacket *pkt);
> +
> +/// @brief Clears the sourcePkts structure.
> +/// @param avctx - AVCodecContext (for logging)
> +/// @param source_pkts - sourcePkts structure
> +/// @return int = 0 on success, < 0 on error
> +int sourcePkts_free(AVCodecContext *avctx, sourcePkts *source_pkts);
> +
> +/// @brief Finds a pkt with the given pts.
> +/// @param avctx - AVCodecContext (for logging)
> +/// @param source_pkts - sourcePkts structure
> +/// @param pts - pts to find
> +/// @return int - physical index of pkt, -1 if not found
> +int sourcePkts_find(AVCodecContext *avctx, sourcePkts *source_pkts, int64_t pts);
> +
> +int sourcePkts_alloc(AVCodecContext *avctx, sourcePkts *source_pkts, int capacity)
> +{
> + assert(source_pkts->pkts == NULL);
> + source_pkts->pkts = av_malloc_array(capacity, sizeof(AVPacket *));
> + if (!source_pkts->pkts)
> + return AVERROR(ENOMEM);
> +
> + source_pkts->capacity = capacity;
> + source_pkts->start_idx = 0;
> + source_pkts->count = 0;
> +
> + av_log(avctx, AV_LOG_TRACE, "sourcePkts_alloc: capacity: %d\n", capacity);
> +
> + return 0;
> +}
> +
> +// Converts a logical index to a physical index.
> +int sourcePkts_idx(sourcePkts *source_pkts, int idx)
> +{
> + return (source_pkts->start_idx + idx) % source_pkts->capacity;
> +}
> +
> +int sourcePkts_find(AVCodecContext *avctx, sourcePkts *source_pkts, int64_t pts)
> +{
> + for (int i = 0; i < source_pkts->count; i++)
> + {
> + int idx = sourcePkts_idx(source_pkts, i);
> + av_log(avctx, AV_LOG_TRACE, "sourcePkts_find: idx: %d, pts: %ld == %ld\n", idx, source_pkts->pkts[idx]->pts, pts);
> + if (source_pkts->pkts[idx]->pts == pts)
> + return idx;
> + }
> +
> + return -1;
> +}
> +
> +int sourcePkts_add(AVCodecContext *avctx, sourcePkts *source_pkts, AVPacket *pkt)
> +{
> + int ret = 0;
> + int idx = 0;
> +
> + if (!pkt || pkt->pts == AV_NOPTS_VALUE) return ret;
> +
> + if (sourcePkts_find(avctx, source_pkts, pkt->pts) >= 0)
> + {
> + av_log(avctx, AV_LOG_TRACE, "sourcePkts_add: pkt already exists, pts: %ld\n", pkt->pts);
> + return ret;
> + }
> +
> + if (source_pkts->capacity == source_pkts->count)
> + {
> + av_log(avctx, AV_LOG_TRACE, "sourcePkts_add: capacity reached, clearing old pkts\n");
> + ret = sourcePkts_clear(avctx, source_pkts, pkt->pts);
> + if (ret < 0) return ret;
> + }
> +
> + idx = sourcePkts_idx(source_pkts, source_pkts->count);
> + source_pkts->pkts[idx] = av_packet_clone(pkt);
> + if (!source_pkts->pkts[idx]) return AVERROR(ENOMEM);
> +
> + source_pkts->count++;
> +
> + av_log(avctx, AV_LOG_TRACE, "sourcePkts_add: added pkt, pts: %ld, size: %d\n", pkt->pts, source_pkts->count);
> +
> + return ret;
> +}
> +
> +int sourcePkts_clear(AVCodecContext *avctx, sourcePkts *source_pkts, int64_t pts)
> +{
> + for (int i = 0; i < source_pkts->count; i++)
> + {
> + if (!source_pkts->pkts[source_pkts->start_idx] || source_pkts->pkts[source_pkts->start_idx]->pts > pts)
> + break;
> +
> + av_log(avctx, AV_LOG_TRACE, "sourcePkts_clear: clearing pkt, pts: %ld\n", source_pkts->pkts[source_pkts->start_idx]->pts);
> +
> + av_packet_unref(source_pkts->pkts[source_pkts->start_idx]);
av_packet_free(&source_pkts->pkts[source_pkts->start_idx]);
> + source_pkts->pkts[source_pkts->start_idx] = NULL;
> + source_pkts->count--;
> + source_pkts->start_idx = sourcePkts_idx(source_pkts, 1);
> + }
> +
> + return 0;
> +}
> +
> +int sourcePkts_free(AVCodecContext *avctx, sourcePkts *source_pkts)
> +{
> + for (int i = 0; i < source_pkts->count; i++)
> + {
> + if (source_pkts->pkts[i]) {
> + av_log(avctx, AV_LOG_TRACE, "sourcePkts_free: freeing pkt, pts: %ld\n", source_pkts->pkts[i]->pts);
> + av_packet_unref(source_pkts->pkts[i]);
av_packet_free(&source_pkts->pkts[i]);
> + }
> + }
> +
> + av_freep(&source_pkts->pkts);
> +
> + return 0;
> +}
> +
> typedef struct CuvidContext
> {
> AVClass *avclass;
> @@ -95,6 +251,8 @@ typedef struct CuvidContext
>
> int *key_frame;
>
> + sourcePkts source_pkts;
> +
> cudaVideoCodec codec_type;
> cudaVideoChromaFormat chroma_format;
>
> @@ -512,6 +670,8 @@ static int cuvid_output_frame(AVCodecContext *avctx, AVFrame *frame)
> if (ret < 0 && ret != AVERROR_EOF)
> return ret;
> ret = cuvid_decode_packet(avctx, pkt);
> +
> + ret = ret < 0 ? ret : sourcePkts_add(avctx, & ctx->source_pkts, pkt);
> av_packet_unref(pkt);
> // cuvid_is_buffer_full() should avoid this.
> if (ret == AVERROR(EAGAIN))
> @@ -530,6 +690,7 @@ static int cuvid_output_frame(AVCodecContext *avctx, AVFrame *frame)
> unsigned int pitch = 0;
> int offset = 0;
> int i;
> + int source_pkt_idx;
>
> memset(¶ms, 0, sizeof(params));
> params.progressive_frame = parsed_frame.dispinfo.progressive_frame;
> @@ -655,6 +816,16 @@ static int cuvid_output_frame(AVCodecContext *avctx, AVFrame *frame)
> }
> }
>
> + source_pkt_idx = sourcePkts_find(avctx, &ctx->source_pkts, frame->pts);
> + if (source_pkt_idx >= 0)
> + {
> + av_log(avctx, AV_LOG_TRACE, "found source_pkt for frame, pts: %ld\n", frame->pts);
> + ff_decode_frame_props_from_pkt(avctx, frame, ctx->source_pkts.pkts[source_pkt_idx]);
> + sourcePkts_clear(avctx, & ctx->source_pkts, frame->pts);
> + } else {
> + av_log(avctx, AV_LOG_TRACE, "no source_pkt for frame, pts: %ld\n", frame->pts);
> + }
> +
> /* CUVIDs opaque reordering breaks the internal pkt logic.
> * So set pkt_pts and clear all the other pkt_ fields.
> */
> @@ -722,6 +893,7 @@ static av_cold int cuvid_decode_end(AVCodecContext *avctx)
> av_freep(&ctx->cuparse_ext);
>
> cuvid_free_functions(&ctx->cvdl);
> + sourcePkts_free(avctx, & ctx->source_pkts);
>
> return 0;
> }
> @@ -948,6 +1120,9 @@ static av_cold int cuvid_decode_init(AVCodecContext *avctx)
> cuda_ctx = device_hwctx->cuda_ctx;
> ctx->cudl = device_hwctx->internal->cuda_dl;
>
> + // To be safe we allocate twice the number of surfaces to avoid the buffer running full with a minimum of 32.
> + sourcePkts_alloc(avctx, &ctx->source_pkts, ctx->nb_surfaces * 2 <= 32 ? 32 : ctx->nb_surfaces * 2);
> +
> memset(&ctx->cuparseinfo, 0, sizeof(ctx->cuparseinfo));
> memset(&seq_pkt, 0, sizeof(seq_pkt));
>
> --
> 2.46.2
>
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