[FFmpeg-devel] [PATCH] Setup for extracting quantization parameters from encoded streams

Juan De León juandl at google.com
Thu Jul 18 02:25:04 EEST 2019


For context
https://docs.google.com/document/d/1WClt3EqhjwdGXhEw386O0wfn3IBQ1Ib-_5emVM1gbnA/edit?usp=sharing
Feel free to comment the doc.

On Wed, Jul 17, 2019 at 4:18 PM Juan De León <juandl at google.com> wrote:

> ---
>  libavfilter/vf_extractqp.c      | 116 ++++++++++++++++++++++++++++++++
>  libavutil/Makefile              |   2 +
>  libavutil/quantization_params.c |  28 ++++++++
>  libavutil/quantization_params.h |  98 +++++++++++++++++++++++++++
>  4 files changed, 244 insertions(+)
>  create mode 100644 libavfilter/vf_extractqp.c
>  create mode 100644 libavutil/quantization_params.c
>  create mode 100644 libavutil/quantization_params.h
>
> diff --git a/libavfilter/vf_extractqp.c b/libavfilter/vf_extractqp.c
> new file mode 100644
> index 0000000000..4332012cc4
> --- /dev/null
> +++ b/libavfilter/vf_extractqp.c
> @@ -0,0 +1,116 @@
> +/*
> + * 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 "libavutil/frame.h"
> +#include "libavutil/opt.h"
> +#include "libavutil/quantization_params.h"
> +#include "libavfilter/avfilter.h"
> +#include "libavfilter/internal.h"
> +
> +typedef struct QPExtractContext {
> +    const AVClass *class;
> +    FILE *stats_file;
> +    char *stats_file_str;
> +} QPExtractContext;
> +
> +#define OFFSET(x) offsetof(QPExtractContext, x)
> +#define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM
> +
> +static const AVOption qpextract_options[] = {
> +    {"stats_file", "Set file to store QP information",
> OFFSET(stats_file_str), AV_OPT_TYPE_STRING, {.str=NULL}, 0, 0, FLAGS },
> +    {"f",          "Set file to store QP information",
> OFFSET(stats_file_str), AV_OPT_TYPE_STRING, {.str=NULL}, 0, 0, FLAGS },
> +    { NULL }
> +};
> +
> +AVFILTER_DEFINE_CLASS(qpextract);
> +
> +static av_cold int init(AVFilterContext *ctx)
> +{
> +    QPExtractContext *s = ctx->priv;
> +
> +    if (s->stats_file_str) {
> +        if (!strcmp(s->stats_file_str, "-")) {
> +            s->stats_file = stdout;
> +        } else {
> +            s->stats_file = fopen(s->stats_file_str, "w");
> +            if (!s->stats_file) {
> +                int err = AVERROR(errno);
> +                char buf[128];
> +                av_strerror(err, buf, sizeof(buf));
> +                av_log(ctx, AV_LOG_ERROR, "Could not open log file %s:
> %s\n",
> +                       s->stats_file_str, buf);
> +                return err;
> +            }
> +        }
> +    }
> +    return 0;
> +}
> +
> +static av_cold int uninit(AVFilterContext *ctx) {
> +    return 0;
> +}
> +
> +static int filter_frame(AVFilterLink *inlink, AVFrame *in) {
> +    AVFilterContext *ctx = inlink->dst;
> +    AVFilterLink *outlink = ctx->outputs[0];
> +    QPExtractContext *s = ctx->priv;
> +    AVFrame *out = NULL;
> +
> +    if (ctx->is_disabled) {
> +        return ff_filter_frame(outlink, in);
> +    }
> +
> +    AVFrameSideData *sd = av_frame_get_side_data(in,
> AV_FRAME_DATA_QUANTIZATION_PARAMS);
> +
> +    if (!sd) {
> +        fprintf(s->stats_file, "no side data");
> +    }
> +    else {
> +        fprintf(s->stats_file, "yes side data");
> +    }
> +
> +    return ff_filter_frame(outlink, in);
> +}
> +
> +static const AVFilterPad qpextract_inputs[] = {
> +    {
> +        .name         = "default",
> +        .type         = AVMEDIA_TYPE_VIDEO,
> +        .filter_frame = filter_frame,
> +    },
> +    { NULL }
> +};
> +
> +static const AVFilterPad qpextract_outputs[] = {
> +    {
> +        .name          = "default",
> +        .type          = AVMEDIA_TYPE_VIDEO,
> +    },
> +    { NULL }
> +};
> +
> +AVFilter ff_vf_qpextract = {
> +    .name          = "extractqp",
> +    .description   = NULL_IF_CONFIG_SMALL("Extract quantization
> parameters."),
> +    .init          = init,
> +    .uninit        = uninit,
> +    .priv_size     = sizeof(QPExtractContext),
> +    .priv_class    = &qpextract_class,
> +    .inputs        = qpextract_inputs,
> +    .outputs       = qpextract_outputs,
> +};
> diff --git a/libavutil/Makefile b/libavutil/Makefile
> index 8a7a44e4b5..be1a9c3a9c 100644
> --- a/libavutil/Makefile
> +++ b/libavutil/Makefile
> @@ -60,6 +60,7 @@ HEADERS = adler32.h
>                \
>            pixdesc.h                                                     \
>            pixelutils.h                                                  \
>            pixfmt.h                                                      \
> +          quantization_params.h                                         \
>            random_seed.h                                                 \
>            rc4.h                                                         \
>            rational.h                                                    \
> @@ -140,6 +141,7 @@ OBJS = adler32.o
>                   \
>         parseutils.o                                                     \
>         pixdesc.o                                                        \
>         pixelutils.o                                                     \
> +       quantization_params.o                                            \
>         random_seed.o                                                    \
>         rational.o                                                       \
>         reverse.o                                                        \
> diff --git a/libavutil/quantization_params.c
> b/libavutil/quantization_params.c
> new file mode 100644
> index 0000000000..96ffd78dbb
> --- /dev/null
> +++ b/libavutil/quantization_params.c
> @@ -0,0 +1,28 @@
> +/*
> + * 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 "libavutil/quantization_params.h"
> +
> +/**
> + * Strings for names of enums, used by Filter
> + */
> +const char* const QP_NAMES_H264[] = {"qp"};
> +const char* const QP_NAMES_VP9[] = {"qydc", "qyac", "quvdc", "quvac",
> "qiydc", "qiyac",
> +                              "qiuvdc", "qiuvac"};
> +const char* const QP_NAMES_AV1[] = {"qydc", "qyac", "qudc", "quac",
> "qvdc", "qvac",
> +                              "qiydc", "qiyac", "qiudc", "qiuac",
> "qivdc", "qivac"};
> \ No newline at end of file
> diff --git a/libavutil/quantization_params.h
> b/libavutil/quantization_params.h
> new file mode 100644
> index 0000000000..e986abe842
> --- /dev/null
> +++ b/libavutil/quantization_params.h
> @@ -0,0 +1,98 @@
> +/*
> + * 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 AVUTIL_QUANTIZATION_PARAMS_H
> +#define AVUTIL_QUANTIZATION_PARAMS_H
> +
> +/**
> + * Data structure for extracting Quantization Parameters codec independent
> + */
> +typedef struct AVQuantizationParams {
> +    /**
> +     * x and y coordinates of the block in pixels
> +     */
> +    int x, y;
> +    /**
> +     * width and height of the block in pixels
> +     */
> +    int w, h;
> +    /**
> +     * qp array, indexed by type according to
> +     * the enum corresponding to the codec
> +     * size depends on codec
> +     */
> +    int *type;
> +} AVQuantizationParams;
> +
> +/**
> + * For storing an array of AVQuantization parameters and its size
> + * To be used as AVFrameSideData
> + */
> +typedef struct AVQuantizationParamsArray {
> +    /**
> +     * AVQuantizationParams block array
> +     */
> +    AVQuantizationParams *qp_arr;
> +    /**
> +     * size of the array
> +     */
> +    int nb_blocks;
> +} AVQuantizationParamsArray;
> +
> +/**
> + * Enums for different codecs to store qp in the type array
> + * Each enum must have an array of strings describing each field
> + * used for output
> + */
> +extern const char* const QP_ENUM_NAMES_H264[];
> +enum QP_ARR_INDEXES_FOR_H264 {
> +        QP_H264 = 0,            // qp value
> +        QP_TYPE_ARR_SIZE_H264   // used for allocating memory
> +};
> +
> +extern const char* const QP_NAMES_VP9[];
> +enum QP_ARR_INDEXES_FOR_VP9 {
> +        QP_YDC_VP9 = 0,
> +        QP_YAC_VP9,
> +        QP_UVDC_VP9,
> +        QP_UVAC_VP9,
> +        QP_INDEX_YDC_VP9,
> +        QP_INDEX_YAC_VP9,
> +        QP_INDEX_UVDC_VP9,
> +        QP_INDEX_UVAC_VP9,
> +        QP_ARR_SIZE_VP9
> +};
> +
> +extern const char* const QP_NAMES_AV1[];
> +enum QP_ARR_INDEXES_FOR_AV1 {
> +        QP_YDC_AV1 = 0,
> +        QP_YAC_AV1,
> +        QP_UDC_AV1,
> +        QP_UAC_AV1,
> +        QP_VDC_AV1,
> +        QP_VAC_AV1,
> +        QP_INDEX_YDC_AV1,
> +        QP_INDEX_YAC_AV1,
> +        QP_INDEX_UDC_AV1,
> +        QP_INDEX_UAC_AV1,
> +        QP_INDEX_VDC_AV1,
> +        QP_INDEX_VAC_AV1,
> +        QP_ARR_SIZE_AV1
> +};
> +
> +#endif /* AVUTIL_QUANTIZATION_PARAMS_H */
> --
> 2.22.0.510.g264f2c817a-goog
>
>


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