[FFmpeg-devel] [PATCH 2/5 v4] avcodec: add an AV1 frame merge bitstream filter
Andreas Rheinhardt
andreas.rheinhardt at gmail.com
Tue Nov 12 23:24:00 EET 2019
James Almer:
> Signed-off-by: James Almer <jamrial at gmail.com>
> ---
> Now using an index to swap fragments.
>
> I noticed that the input packet containing props is not necessarily the first
> in a TU, so adapted the code accordingly. This fixes warnings about missing
> timestamps when trying to merge the output of av1_frame_split, where the source
> had the visible frames at the end of a TU rather than at the beginning.
>
> Not going to bother with indexes for the packets. av_packet_move_ref() is far
> from expensive, unlike creating buffer references and expanding the fragment's
> unit buffer.
>
> configure | 1 +
> libavcodec/Makefile | 1 +
> libavcodec/av1_frame_merge_bsf.c | 169 +++++++++++++++++++++++++++++++
> libavcodec/bitstream_filters.c | 1 +
> 4 files changed, 172 insertions(+)
> create mode 100644 libavcodec/av1_frame_merge_bsf.c
>
> diff --git a/configure b/configure
> index 1de90e93fd..70f60997c1 100755
> --- a/configure
> +++ b/configure
> @@ -3115,6 +3115,7 @@ vc1_parser_select="vc1dsp"
>
> # bitstream_filters
> aac_adtstoasc_bsf_select="adts_header"
> +av1_frame_merge_bsf_select="cbs_av1"
> av1_frame_split_bsf_select="cbs_av1"
> av1_metadata_bsf_select="cbs_av1"
> eac3_core_bsf_select="ac3_parser"
> diff --git a/libavcodec/Makefile b/libavcodec/Makefile
> index b990c6ba87..006a472a6d 100644
> --- a/libavcodec/Makefile
> +++ b/libavcodec/Makefile
> @@ -1075,6 +1075,7 @@ OBJS-$(CONFIG_XMA_PARSER) += xma_parser.o
> # bitstream filters
> OBJS-$(CONFIG_AAC_ADTSTOASC_BSF) += aac_adtstoasc_bsf.o mpeg4audio.o
> OBJS-$(CONFIG_AV1_METADATA_BSF) += av1_metadata_bsf.o
> +OBJS-$(CONFIG_AV1_FRAME_MERGE_BSF) += av1_frame_merge_bsf.o
> OBJS-$(CONFIG_AV1_FRAME_SPLIT_BSF) += av1_frame_split_bsf.o
> OBJS-$(CONFIG_CHOMP_BSF) += chomp_bsf.o
> OBJS-$(CONFIG_DUMP_EXTRADATA_BSF) += dump_extradata_bsf.o
> diff --git a/libavcodec/av1_frame_merge_bsf.c b/libavcodec/av1_frame_merge_bsf.c
> new file mode 100644
> index 0000000000..96a9e6e863
> --- /dev/null
> +++ b/libavcodec/av1_frame_merge_bsf.c
> @@ -0,0 +1,169 @@
> +/*
> + * Copyright (c) 2019 James Almer <jamrial at gmail.com>
> + *
> + * This file is part of FFmpeg.
> + *
> + * FFmpeg is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU Lesser General Public
> + * License as published by the Free Software Foundation; either
> + * version 2.1 of the License, or (at your option) any later version.
> + *
> + * FFmpeg is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
> + * Lesser General Public License for more details.
> + *
> + * You should have received a copy of the GNU Lesser General Public
> + * License along with FFmpeg; if not, write to the Free Software
> + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
> + */
> +
> +#include "avcodec.h"
> +#include "bsf.h"
> +#include "cbs.h"
> +#include "cbs_av1.h"
> +
> +typedef struct AV1FMergeContext {
> + CodedBitstreamContext *cbc;
> + CodedBitstreamFragment frag[2];
> + AVPacket *pkt, *in;
> + int idx;
> +} AV1FMergeContext;
> +
> +static int av1_frame_merge_filter(AVBSFContext *bsf, AVPacket *out)
> +{
> + AV1FMergeContext *ctx = bsf->priv_data;
> + CodedBitstreamFragment *frag = &ctx->frag[ctx->idx], *tu = &ctx->frag[!ctx->idx];
> + AVPacket *in = ctx->in, *buffer_pkt = ctx->pkt;
> + int err, i;
> +
> + err = ff_bsf_get_packet_ref(bsf, in);
> + if (err < 0) {
> + if (err == AVERROR_EOF && tu->nb_units > 0)
> + goto eof;
> + return err;
> + }
> +
> + err = ff_cbs_read_packet(ctx->cbc, frag, in);
> + if (err < 0) {
> + av_log(bsf, AV_LOG_ERROR, "Failed to read packet.\n");
> + goto fail;
> + }
> +
> + if (frag->nb_units == 0) {
> + av_log(bsf, AV_LOG_ERROR, "No OBU in packet.\n");
> + err = AVERROR_INVALIDDATA;
> + goto fail;
> + }
> +
> + if (tu->nb_units == 0 && frag->units[0].type != AV1_OBU_TEMPORAL_DELIMITER) {
> + av_log(bsf, AV_LOG_ERROR, "Missing Temporal Delimiter.\n");
> + err = AVERROR_INVALIDDATA;
> + goto fail;
> + }
> +
> + if (tu->nb_units > 0 && frag->units[0].type == AV1_OBU_TEMPORAL_DELIMITER) {
> +eof:
> + err = ff_cbs_write_packet(ctx->cbc, buffer_pkt, tu);
> + if (err < 0) {
> + av_log(bsf, AV_LOG_ERROR, "Failed to write packet.\n");
> + goto fail;
> + }
> + av_packet_move_ref(out, buffer_pkt);
> +
> + ff_cbs_fragment_reset(ctx->cbc, tu);
> +
> + for (i = 1; i < frag->nb_units; i++) {
> + if (frag->units[i].type == AV1_OBU_TEMPORAL_DELIMITER) {
> + av_log(bsf, AV_LOG_ERROR, "Temporal Delimiter in the middle of a packet.\n");
> + err = AVERROR_INVALIDDATA;
> + goto fail;
> + }
> + }
You can move the above loop to before this block. This allows to
remove the equivalent check in the loop below as well as unreferencing
the out packet on failure as it will always be clean.
> + // Swap fragment index, to avoid copying fragment references.
> + ctx->idx = !ctx->idx;
> +
> + // Buffer the packet if it has a timestamp.
> + if (in->pts != AV_NOPTS_VALUE)
> + av_packet_move_ref(buffer_pkt, in);
You could add an else here. You could do the same with the other unref
below.
(You could even combine the two: put the insertion of unit content
into the else branch of this block, set err/ret to 0 in this block and
to AVERROR(EAGAIN) in the else branch and use the below check for
buffering. Resetting the fragments could also be combined with
ff_cbs_fragment_reset(ctx->cbc, &ctx->frag[ctx->idx]).)
> + av_packet_unref(in);
> +
> + return 0;
> + }
> +
> + // Buffer packets with timestamps. There should be at most one per TU, be it split or not.
> + if (!buffer_pkt->data && in->pts != AV_NOPTS_VALUE)
> + av_packet_move_ref(buffer_pkt, in);
> +
> + for (i = 0; i < frag->nb_units; i++) {
> + if (i && frag->units[i].type == AV1_OBU_TEMPORAL_DELIMITER) {
> + av_log(bsf, AV_LOG_ERROR, "Temporal Delimiter in the middle of a packet.\n");
> + err = AVERROR_INVALIDDATA;
> + goto fail;
> + }
> + err = ff_cbs_insert_unit_content(ctx->cbc, tu, -1, frag->units[i].type,
> + frag->units[i].content, frag->units[i].content_ref);
> + if (err < 0)
> + goto fail;
> + }
> + ff_cbs_fragment_reset(ctx->cbc, frag);
> + av_packet_unref(in);
> +
> + return AVERROR(EAGAIN);
> +
> +fail:
> + ff_cbs_fragment_reset(ctx->cbc, tu);
> + ff_cbs_fragment_reset(ctx->cbc, frag);
> + av_packet_unref(buffer_pkt);
> + av_packet_unref(in);
How about replacing the above with a call to av1_frame_merge_flush()?
> + av_packet_unref(out);
> +
> + return err;
> +}
> +
> +static int av1_frame_merge_init(AVBSFContext *bsf)
> +{
> + AV1FMergeContext *ctx = bsf->priv_data;
> +
> + ctx->in = av_packet_alloc();
> + ctx->pkt = av_packet_alloc();
> + if (!ctx->in || !ctx->pkt)
> + return AVERROR(ENOMEM);
> +
> + return ff_cbs_init(&ctx->cbc, AV_CODEC_ID_AV1, bsf);
> +}
> +
> +static void av1_frame_merge_flush(AVBSFContext *bsf)
> +{
> + AV1FMergeContext *ctx = bsf->priv_data;
> +
> + ff_cbs_fragment_reset(ctx->cbc, &ctx->frag[0]);
> + ff_cbs_fragment_reset(ctx->cbc, &ctx->frag[1]);
> + av_packet_unref(ctx->in);
> + av_packet_unref(ctx->pkt);
> +}
> +
> +static void av1_frame_merge_close(AVBSFContext *bsf)
> +{
> + AV1FMergeContext *ctx = bsf->priv_data;
> +
> + ff_cbs_fragment_free(ctx->cbc, &ctx->frag[0]);
> + ff_cbs_fragment_free(ctx->cbc, &ctx->frag[1]);
> + av_packet_free(&ctx->in);
> + av_packet_free(&ctx->pkt);
> + ff_cbs_close(&ctx->cbc);
> +}
> +
> +static const enum AVCodecID av1_frame_merge_codec_ids[] = {
> + AV_CODEC_ID_AV1, AV_CODEC_ID_NONE,
> +};
> +
> +const AVBitStreamFilter ff_av1_frame_merge_bsf = {
> + .name = "av1_frame_merge",
> + .priv_data_size = sizeof(AV1FMergeContext),
> + .init = av1_frame_merge_init,
> + .flush = av1_frame_merge_flush,
> + .close = av1_frame_merge_close,
> + .filter = av1_frame_merge_filter,
> + .codec_ids = av1_frame_merge_codec_ids,
> +};
> diff --git a/libavcodec/bitstream_filters.c b/libavcodec/bitstream_filters.c
> index 463003966a..6b5ffe4d70 100644
> --- a/libavcodec/bitstream_filters.c
> +++ b/libavcodec/bitstream_filters.c
> @@ -25,6 +25,7 @@
> #include "bsf.h"
>
> extern const AVBitStreamFilter ff_aac_adtstoasc_bsf;
> +extern const AVBitStreamFilter ff_av1_frame_merge_bsf;
> extern const AVBitStreamFilter ff_av1_frame_split_bsf;
> extern const AVBitStreamFilter ff_av1_metadata_bsf;
> extern const AVBitStreamFilter ff_chomp_bsf;
>
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