[FFmpeg-devel] [PATCH 07/27] cbs: Implement common parts of cbs-based bitstream filters separately
Andreas Rheinhardt
andreas.rheinhardt at gmail.com
Sat Jan 2 00:18:13 EET 2021
Mark Thompson:
> This allows removal of a lot of duplicated code between BSFs.
> ---
> libavcodec/Makefile | 2 +-
> libavcodec/cbs_bsf.c | 161 +++++++++++++++++++++++++++++++++++++++++++
> libavcodec/cbs_bsf.h | 100 +++++++++++++++++++++++++++
> 3 files changed, 262 insertions(+), 1 deletion(-)
> create mode 100644 libavcodec/cbs_bsf.c
> create mode 100644 libavcodec/cbs_bsf.h
>
> diff --git a/libavcodec/Makefile b/libavcodec/Makefile
> index 6e12a8171d..8f50217ad4 100644
> --- a/libavcodec/Makefile
> +++ b/libavcodec/Makefile
> @@ -69,7 +69,7 @@ OBJS-$(CONFIG_AUDIODSP) += audiodsp.o
> OBJS-$(CONFIG_BLOCKDSP) += blockdsp.o
> OBJS-$(CONFIG_BSWAPDSP) += bswapdsp.o
> OBJS-$(CONFIG_CABAC) += cabac.o
> -OBJS-$(CONFIG_CBS) += cbs.o
> +OBJS-$(CONFIG_CBS) += cbs.o cbs_bsf.o
> OBJS-$(CONFIG_CBS_AV1) += cbs_av1.o
> OBJS-$(CONFIG_CBS_H264) += cbs_h2645.o cbs_sei.o h2645_parse.o
> OBJS-$(CONFIG_CBS_H265) += cbs_h2645.o cbs_sei.o h2645_parse.o
> diff --git a/libavcodec/cbs_bsf.c b/libavcodec/cbs_bsf.c
> new file mode 100644
> index 0000000000..429f360014
> --- /dev/null
> +++ b/libavcodec/cbs_bsf.c
> @@ -0,0 +1,161 @@
> +/*
> + * 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 "bsf_internal.h"
> +#include "cbs_bsf.h"
> +
> +static int ff_cbs_bsf_update_side_data(AVBSFContext *bsf, AVPacket *pkt)
The ff_ prefix is not for static functions.
> +{
> + CBSBSFContext *ctx = bsf->priv_data;
> + CodedBitstreamFragment *frag = &ctx->fragment;
> + uint8_t *side_data;
> + int side_data_size;
> + int err;
> +
> + side_data = av_packet_get_side_data(pkt, AV_PKT_DATA_NEW_EXTRADATA,
> + &side_data_size);
> + if (!side_data_size)
> + return 0;
> +
> + err = ff_cbs_read(ctx->input, frag, side_data, side_data_size);
> + if (err < 0) {
> + av_log(bsf, AV_LOG_ERROR,
> + "Failed to read extradata from packet side data.\n");
> + return err;
> + }
> +
> + err = ctx->type->update_fragment(bsf, NULL, frag);
> + if (err < 0)
> + goto fail;
This is inconsistent: All the other errors paths out of this function do
not reset the fragment; and that is fine, because the one and only
caller already does so. (Did you intend for this function to be more
standalone?)
> +
> + err = ff_cbs_write_fragment_data(ctx->output, frag);
> + if (err < 0) {
> + av_log(bsf, AV_LOG_ERROR,
> + "Failed to write extradata into packet side data.\n");
> + return err;
> + }
> +
> + side_data = av_packet_new_side_data(pkt, AV_PKT_DATA_NEW_EXTRADATA,
> + frag->data_size);
> + if (!side_data)
> + return AVERROR(ENOMEM);
> + memcpy(side_data, frag->data, frag->data_size);
> +
> + err = 0;
> +fail:
> + ff_cbs_fragment_reset(frag);
> + return err;
> +}
> +
> +int ff_cbs_bsf_filter(AVBSFContext *bsf, AVPacket *pkt)
> +{
> + CBSBSFContext *ctx = bsf->priv_data;
> + CodedBitstreamFragment *frag = &ctx->fragment;
> + int err;
> +
> + err = ff_bsf_get_packet_ref(bsf, pkt);
> + if (err < 0)
> + return err;
> +
> + err = ff_cbs_bsf_update_side_data(bsf, pkt);
> + if (err < 0)
> + goto fail;
> +
> + err = ff_cbs_read_packet(ctx->input, frag, pkt);
> + if (err < 0) {
> + av_log(bsf, AV_LOG_ERROR, "Failed to read %s from packet.\n",
> + ctx->type->fragment_name);
> + goto fail;
> + }
> +
> + if (frag->nb_units == 0) {
> + av_log(bsf, AV_LOG_ERROR, "No %s found in packet.\n",
> + ctx->type->unit_name);
> + err = AVERROR_INVALIDDATA;
> + goto fail;
> + }
> +
> + err = ctx->type->update_fragment(bsf, pkt, frag);
> + if (err < 0)
> + goto fail;
> +
> + err = ff_cbs_write_packet(ctx->output, pkt, frag);
> + if (err < 0) {
> + av_log(bsf, AV_LOG_ERROR, "Failed to write %s into packet.\n",
> + ctx->type->fragment_name);
> + goto fail;
> + }
> +
> + err = 0;
> +fail:
> + ff_cbs_fragment_reset(frag);
> +
> + if (err < 0)
> + av_packet_unref(pkt);
> +
> + return err;
> +}
> +
> +int ff_cbs_bsf_init(AVBSFContext *bsf, const CBSBSFType *type)
> +{
> + CBSBSFContext *ctx = bsf->priv_data;
> + CodedBitstreamFragment *frag = &ctx->fragment;
> + int err;
> +
> + ctx->type = type;
> +
> + err = ff_cbs_init(&ctx->input, type->codec_id, bsf);
> + if (err < 0)
> + return err;
> +
> + err = ff_cbs_init(&ctx->output, type->codec_id, bsf);
> + if (err < 0)
> + return err;
> +
> + if (bsf->par_in->extradata) {
> + err = ff_cbs_read_extradata(ctx->input, frag, bsf->par_in);
> + if (err < 0) {
> + av_log(bsf, AV_LOG_ERROR, "Failed to read extradata.\n");
> + goto fail;
> + }
> +
> + err = type->update_fragment(bsf, NULL, frag);
> + if (err < 0)
> + goto fail;
> +
> + err = ff_cbs_write_extradata(ctx->output, bsf->par_out, frag);
> + if (err < 0) {
> + av_log(bsf, AV_LOG_ERROR, "Failed to write extradata.\n");
> + goto fail;
> + }
> + }
> +
> + err = 0;
> +fail:
> + ff_cbs_fragment_reset(frag);
> + return err;
> +}
> +
> +void ff_cbs_bsf_close(AVBSFContext *bsf)
> +{
> + CBSBSFContext *ctx = bsf->priv_data;
> +
> + ff_cbs_fragment_free(&ctx->fragment);
> + ff_cbs_close(&ctx->input);
> + ff_cbs_close(&ctx->output);
> +}
> diff --git a/libavcodec/cbs_bsf.h b/libavcodec/cbs_bsf.h
> new file mode 100644
> index 0000000000..8cab3f144c
> --- /dev/null
> +++ b/libavcodec/cbs_bsf.h
> @@ -0,0 +1,100 @@
> +/*
> + * 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
> + */
> +
> +#ifndef AVCODEC_CBS_BSF_H
> +#define AVCODEC_CBS_BSF_H
> +
> +#include "cbs.h"
> +
> +
> +typedef struct CBSBSFType {
> + enum AVCodecID codec_id;
> +
> + // Name of a frame fragment in this codec (e.g. "access unit",
> + // "temporal unit").
> + const char *fragment_name;
> +
> + // Name of a unit for this BSF, for use in error messages (e.g.
> + // "NAL unit", "OBU").
> + const char *unit_name;
> +
> + // Update the content of a fragment with whatever metadata changes
> + // are desired. The associated AVPacket is provided so that any side
> + // data associated with the fragment can be inspected or edited. If
> + // pkt is NULL, then an extradata header fragment is being updated.
> + int (*update_fragment)(AVBSFContext *bsf, AVPacket *pkt,
> + CodedBitstreamFragment *frag);
> +} CBSBSFType;
> +
> +typedef struct CBSBSFContext {
> + const AVClass *class;
> + const CBSBSFType *type;
> +
> + CodedBitstreamContext *input;
> + CodedBitstreamContext *output;
> + CodedBitstreamFragment fragment;
> +} CBSBSFContext;
> +
> +
> +int ff_cbs_bsf_filter(AVBSFContext *bsf, AVPacket *pkt);
> +int ff_cbs_bsf_init(AVBSFContext *bsf, const CBSBSFType *type);
> +void ff_cbs_bsf_close(AVBSFContext *bsf);
> +
> +
> +// Options for element manipulation.
> +enum {
> + // Pass this element through unchanged.
> + BSF_ELEMENT_PASS,
> + // Insert this element, replacing any existing instances of it.
> + // Associated values may be provided explicitly (as addtional options)
> + // or implicitly (either as side data or deduced from other parts of
> + // the stream).
> + BSF_ELEMENT_INSERT,
> + // Remove this element if it appears in the stream.
> + BSF_ELEMENT_REMOVE,
> + // Extract this element to side data, so that further manipulation
> + // can happen elsewhere.
> + BSF_ELEMENT_EXTRACT,
> +};
> +
> +#define BSF_ELEMENT_OPTIONS_PIR(name, help, field, unit_name) \
> + { name, help, OFFSET(field), AV_OPT_TYPE_INT, \
> + { .i64 = BSF_ELEMENT_PASS }, \
> + BSF_ELEMENT_PASS, BSF_ELEMENT_REMOVE, FLAGS, unit_name }, \
> + { "pass", NULL, 0, AV_OPT_TYPE_CONST, \
> + { .i64 = BSF_ELEMENT_PASS }, .flags = FLAGS, .unit = unit_name }, \
> + { "insert", NULL, 0, AV_OPT_TYPE_CONST, \
> + { .i64 = BSF_ELEMENT_INSERT }, .flags = FLAGS, .unit = unit_name }, \
> + { "remove", NULL, 0, AV_OPT_TYPE_CONST, \
> + { .i64 = BSF_ELEMENT_REMOVE }, .flags = FLAGS, .unit = unit_name }
> +
> +#define BSF_ELEMENT_OPTIONS_PIRE(name, help, field, unit_name) \
> + { name, help, OFFSET(field), AV_OPT_TYPE_INT, \
> + { .i64 = BSF_ELEMENT_PASS }, \
> + BSF_ELEMENT_PASS, BSF_ELEMENT_EXTRACT, FLAGS, unit_name }, \
> + { "pass", NULL, 0, AV_OPT_TYPE_CONST, \
> + { .i64 = BSF_ELEMENT_PASS }, .flags = FLAGS, .unit = unit_name }, \
> + { "insert", NULL, 0, AV_OPT_TYPE_CONST, \
> + { .i64 = BSF_ELEMENT_INSERT }, .flags = FLAGS, .unit = unit_name }, \
> + { "remove", NULL, 0, AV_OPT_TYPE_CONST, \
> + { .i64 = BSF_ELEMENT_REMOVE }, .flags = FLAGS, .unit = unit_name }, \
> + { "extract", NULL, 0, AV_OPT_TYPE_CONST, \
> + { .i64 = BSF_ELEMENT_EXTRACT }, .flags = FLAGS, .unit = unit_name } \
> +
> +
> +#endif /* AVCODEC_CBS_BSF_H */
>
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