[FFmpeg-devel] [PATCH] Extract QP from h264 encoded videos

Andrey Semashev andrey.semashev at gmail.com
Tue Jul 30 12:11:53 EEST 2019


On 7/30/19 5:39 AM, Juan De León wrote:
> I tried to fix all you suggested, please have a look and let me know what you think.
> 
> design doc: https://docs.google.com/document/d/1WClt3EqhjwdGXhEw386O0wfn3IBQ1Ib-_5emVM1gbnA/edit?usp=sharing
> 
> Signed-off-by: Juan De León <juandl at google.com>
> ---
>   libavutil/Makefile              |   2 +
>   libavutil/frame.h               |   6 ++
>   libavutil/quantization_params.c |  42 ++++++++++++
>   libavutil/quantization_params.h | 114 ++++++++++++++++++++++++++++++++
>   4 files changed, 164 insertions(+)
>   create mode 100644 libavutil/quantization_params.c
>   create mode 100644 libavutil/quantization_params.h
> 
> 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/frame.h b/libavutil/frame.h
> index 5d3231e7bb..b64fd9c02c 100644
> --- a/libavutil/frame.h
> +++ b/libavutil/frame.h
> @@ -179,6 +179,12 @@ enum AVFrameSideDataType {
>        * array element is implied by AVFrameSideData.size / AVRegionOfInterest.self_size.
>        */
>       AV_FRAME_DATA_REGIONS_OF_INTEREST,
> +    /**
> +     * To extract quantization parameters from supported decoders.
> +     * The data is stored as AVQuantizationParamsArray type, described in
> +     * libavuitl/quantization_params.h
> +     */
> +    AV_FRAME_DATA_QUANTIZATION_PARAMS,
>   };
>   
>   enum AVActiveFormatDescription {
> diff --git a/libavutil/quantization_params.c b/libavutil/quantization_params.c
> new file mode 100644
> index 0000000000..fc51b55eee
> --- /dev/null
> +++ b/libavutil/quantization_params.c
> @@ -0,0 +1,42 @@
> +/*
> + * 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"
> +#include "libavutil/mem.h"
> +
> +static const char* const QP_NAMES_H264[] = {"qpy", "qpuv"};
> +
> +static const char* const QP_NAMES_VP9[] = {"qyac", "qydc", "quvdc", "quvac",
> +                                           "qiyac", "qiydc", "qiuvdc", "qiuvac"};
> +
> +static const char* const QP_NAMES_AV1[] = {"qydc", "qyac", "qudc", "quac", "qvdc", "qvac",
> +                                      "qiydc", "qiyac", "qiudc", "qiuac", "qivdc", "qivac"};
> +
> +char* av_get_qp_type_string(enum AVExtractQPSupportedCodecs codec_id, int index)
> +{
> +    switch (codec_id) {
> +        case AV_EXTRACT_QP_CODEC_ID_H264:
> +            return index < AV_QP_ARR_SIZE_H264 ? av_strdup(QP_NAMES_H264[index]) :NULL;
> +        case AV_EXTRACT_QP_CODEC_ID_VP9:
> +            return index < AV_QP_ARR_SIZE_VP9  ? av_strdup(QP_NAMES_VP9[index])  :NULL;
> +        case AV_EXTRACT_QP_CODEC_ID_AV1:
> +            return index < AV_QP_ARR_SIZE_AV1  ? av_strdup(QP_NAMES_AV1[index])  :NULL;
> +        default:
> +            return NULL;
> +    }
> +}
> diff --git a/libavutil/quantization_params.h b/libavutil/quantization_params.h
> new file mode 100644
> index 0000000000..d123aade3b
> --- /dev/null
> +++ b/libavutil/quantization_params.h
> @@ -0,0 +1,114 @@
> +/*
> + * 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
> +
> +/*
> + * Supported decoders
> + */
> +enum AVExtractQPSupportedCodecs {
> +    AV_EXTRACT_QP_CODEC_ID_H264 = 0,
> +    AV_EXTRACT_QP_CODEC_ID_VP9,
> +    AV_EXTRACT_QP_CODEC_ID_AV1,
> +};

Just a thought. If you need codec ids and implement codec-specific 
functionality, then this whole thing probably belongs to libavcodec, not 
libavutil.

> +
> +/**
> + * Enums for different codecs to store qp in the type array
> + * Each enum must have an array of strings describing each field
> + * declared in quantization_params.c
> + */
> +
> +enum AVQPArrIndexesH264 {
> +    AV_QP_Y_H264 = 0,       // qp value index in qp_type array
> +    AV_QP_UV_H264,
> +    AV_QP_ARR_SIZE_H264     // number of QP stored for this codec
> +};
> +
> +enum AVQPArrIndexesVP9 {
> +    AV_QP_YAC_VP9 = 0,    // get_dc_quant[][AV_QP_INDEX_YAC_VP9]
> +    AV_QP_YDC_VP9,        // get_dc_quant[][AV_QP_INDEX_YDC_VP9]
> +    AV_QP_UVDC_VP9,       // get_dc_quant[][AV_QP_INDEX_UVDC_VP9]
> +    AV_QP_UVAC_VP9,       // get_ac_quant[][AV_QP_INDEX_UVAC_VP9]
> +    AV_QP_INDEX_YAC_VP9,  // base_q_idx
> +    AV_QP_INDEX_YDC_VP9,  // base_q_idx+delta_q_y_dc
> +    AV_QP_INDEX_UVDC_VP9, // base_q_idx+delta_q_uv_dc
> +    AV_QP_INDEX_UVAC_VP9, // base_q_idx+delta_q_uv_ac
> +    AV_QP_ARR_SIZE_VP9
> +};
> +
> +enum AVQPArrIndexesAV1 {
> +    AV_QP_YDC_AV1 = 0,
> +    AV_QP_YAC_AV1,
> +    AV_QP_UDC_AV1,
> +    AV_QP_UAC_AV1,
> +    AV_QP_VDC_AV1,
> +    AV_QP_VAC_AV1,
> +    AV_QP_INDEX_YDC_AV1,
> +    AV_QP_INDEX_YAC_AV1,
> +    AV_QP_INDEX_UDC_AV1,
> +    AV_QP_INDEX_UAC_AV1,
> +    AV_QP_INDEX_VDC_AV1,
> +    AV_QP_INDEX_VAC_AV1,
> +    AV_QP_ARR_SIZE_AV1
> +};
> +
> +/**
> + * 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
> +     */
> +    int qp_type[AV_QP_ARR_SIZE_AV1];
> +} AVQuantizationParams;
> +
> +/**
> + * For storing an array of AVQuantization parameters and its size
> + * Used as AVFrameSideData
> + */
> +typedef struct AVQuantizationParamsArray {
> +    /**
> +     * Array of AVQuantizationParams type blocks
> +     */
> +    AVQuantizationParams *qp_block_array;
> +    /**
> +     * size of the array
> +     */
> +    int nb_blocks;
> +    /**
> +     * Stores an id corresponding to one of the suppported codecs
> +     */
> +    enum AVExtractQPSupportedCodecs codec_id;
> +} AVQuantizationParamsArray;
> +
> +/**
> + * Get the string describing the qp type for the given codec
> + */
> +char* av_get_qp_type_string(enum AVExtractQPSupportedCodecs codec_id, int index);
> +
> +#endif /* AVUTIL_QUANTIZATION_PARAMS_H */
> 



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