[FFmpeg-devel] doc/examples: Add qsv_transcode example

From: Wenbin Chen <wenbin.chen@intel.com>

Add qsv_transcode example which shows how to use qsv to do hardware
accelerated transcoding, also show how to dynamically set encoding
parameters.

examples:
Normal usage:
qsv_transcode input.mp4 h264_qsv output.mp4 "g 60"

Dynamic setting usage:
qsv_transcode input.mp4 hevc_qsv output.mp4 "g 60 asyne_depth 1"
100 "g 120"
This command initializes codec with gop_size 60 and change it to
120 after 100 frames

Signed-off-by: Wenbin Chen <wenbin.chen@intel.com>
---
 configure                    |   2 +
 doc/examples/.gitignore      |   1 +
 doc/examples/Makefile        |   1 +
 doc/examples/qsv_transcode.c | 440 +++++++++++++++++++++++++++++++++++
 4 files changed, 444 insertions(+)
 create mode 100644 doc/examples/qsv_transcode.c

On Mon, 2022-10-31 at 15:22 +0800, wenbin.chen-at-intel.com@ffmpeg.org wrote:
> From: Wenbin Chen <wenbin.chen@intel.com>
> 
> Add qsv_transcode example which shows how to use qsv to do hardware
> accelerated transcoding, also show how to dynamically set encoding
> parameters.
> 
> examples:
> Normal usage:
> qsv_transcode input.mp4 h264_qsv output.mp4 "g 60"
> 
> Dynamic setting usage:
> qsv_transcode input.mp4 hevc_qsv output.mp4 "g 60 asyne_depth 1"
> 100 "g 120"
> This command initializes codec with gop_size 60 and change it to
> 120 after 100 frames
> 
> Signed-off-by: Wenbin Chen <wenbin.chen@intel.com>
> ---
>  configure                    |   2 +
>  doc/examples/.gitignore      |   1 +
>  doc/examples/Makefile        |   1 +
>  doc/examples/qsv_transcode.c | 440 +++++++++++++++++++++++++++++++++++
>  4 files changed, 444 insertions(+)
>  create mode 100644 doc/examples/qsv_transcode.c
> 
> diff --git a/configure b/configure
> index 70c9e41dcc..a8b4496465 100755
> --- a/configure
> +++ b/configure
> @@ -1748,6 +1748,7 @@ EXAMPLE_LIST="
>      transcoding_example
>      vaapi_encode_example
>      vaapi_transcode_example
> +    qsv_transcode_example
>  "
>  
>  EXTERNAL_AUTODETECT_LIBRARY_LIST="
> @@ -3811,6 +3812,7 @@ transcode_aac_example_deps="avcodec avformat swresample"
>  transcoding_example_deps="avfilter avcodec avformat avutil"
>  vaapi_encode_example_deps="avcodec avutil h264_vaapi_encoder"
>  vaapi_transcode_example_deps="avcodec avformat avutil h264_vaapi_encoder"
> +qsv_transcode_example_deps="avcodec avformat avutil h264_qsv_encoder"
>  
>  # EXTRALIBS_LIST
>  cpu_init_extralibs="pthreads_extralibs"
> diff --git a/doc/examples/.gitignore b/doc/examples/.gitignore
> index 44960e1de7..d787afdd4c 100644
> --- a/doc/examples/.gitignore
> +++ b/doc/examples/.gitignore
> @@ -22,3 +22,4 @@
>  /transcoding
>  /vaapi_encode
>  /vaapi_transcode
> +/qsv_transcode
> diff --git a/doc/examples/Makefile b/doc/examples/Makefile
> index 81bfd34d5d..f937fbefda 100644
> --- a/doc/examples/Makefile
> +++ b/doc/examples/Makefile
> @@ -21,6 +21,7 @@ EXAMPLES-$(CONFIG_TRANSCODE_AAC_EXAMPLE)     +=
> transcode_aac
>  EXAMPLES-$(CONFIG_TRANSCODING_EXAMPLE)       += transcoding
>  EXAMPLES-$(CONFIG_VAAPI_ENCODE_EXAMPLE)      += vaapi_encode
>  EXAMPLES-$(CONFIG_VAAPI_TRANSCODE_EXAMPLE)   += vaapi_transcode
> +EXAMPLES-$(CONFIG_QSV_TRANSCODE_EXAMPLE)     += qsv_transcode
>  
>  EXAMPLES       := $(EXAMPLES-yes:%=doc/examples/%$(PROGSSUF)$(EXESUF))
>  EXAMPLES_G     := $(EXAMPLES-yes:%=doc/examples/%$(PROGSSUF)_g$(EXESUF))
> diff --git a/doc/examples/qsv_transcode.c b/doc/examples/qsv_transcode.c
> new file mode 100644
> index 0000000000..9b37bbea9f
> --- /dev/null
> +++ b/doc/examples/qsv_transcode.c
> @@ -0,0 +1,440 @@
> +/*
> + * Quick Sync Video (video transcoding) transcode sample
> + *
> + * Permission is hereby granted, free of charge, to any person obtaining a
> copy
> + * of this software and associated documentation files (the "Software"), to
> deal
> + * in the Software without restriction, including without limitation the
> rights
> + * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
> + * copies of the Software, and to permit persons to whom the Software is
> + * furnished to do so, subject to the following conditions:
> + *
> + * The above copyright notice and this permission notice shall be included in
> + * all copies or substantial portions of the Software.
> + *
> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
> + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
> + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
> + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
> + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
> FROM,
> + * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
> + * THE SOFTWARE.
> + */
> +
> +/**
> + * @file
> + * Intel QSV-accelerated transcoding example.
> + *
> + * @example qsv_transcode.c
> + * This example shows how to do QSV-accelerated transcoding and how to
> + * dynamically change encoder's option.
> + * Usage: qsv_transcode input_stream codec output_stream initial option
> + *                      { frame_number new_option }
> + * e.g: - qsv_transcode input.mp4 h264_qsv output_h264.mp4 "g 60"
> + *      - qsv_transcode input.mp4 hevc_qsv output_hevc.mp4 "g 60 async_depth
> 1"
> + *                      100 "g 120"
> + *         (initialize codec with gop_size 60 and change it to 120 after 100
> + *          frames)
> + */
> +
> +#include <stdio.h>
> +#include <errno.h>
> +
> +#include <libavutil/hwcontext.h>
> +#include <libavcodec/avcodec.h>
> +#include <libavformat/avformat.h>
> +#include <libavutil/opt.h>
> +
> +static AVFormatContext *ifmt_ctx = NULL, *ofmt_ctx = NULL;
> +static AVBufferRef *hw_device_ctx = NULL;
> +static AVCodecContext *decoder_ctx = NULL, *encoder_ctx = NULL;
> +static int video_stream = -1;
> +
> +typedef struct DynamicSetting {
> +    int frame_number;
> +    char* optstr;
> +} DynamicSetting;
> +static DynamicSetting *dynamic_setting;
> +static int setting_number;
> +static int current_setting_number;
> +
> +static int str_to_dict(char* optstr, AVDictionary **opt)
> +{
> +    char *key, *value;
> +    if (strlen(optstr) == 0)
> +        return 0;
> +    key = strtok(optstr, " ");
> +    if (key == NULL)
> +        return AVERROR(ENAVAIL);
> +    value = strtok(NULL, " ");
> +    if (value == NULL)
> +        return AVERROR(ENAVAIL);
> +    av_dict_set(opt, key, value, 0);
> +    do {
> +        key = strtok(NULL, " ");
> +        if (key == NULL)
> +            return 0;
> +        value = strtok(NULL, " ");
> +        if (value == NULL)
> +            return AVERROR(ENAVAIL);
> +        av_dict_set(opt, key, value, 0);
> +    } while(key != NULL);
> +    return 0;
> +}
> +
> +static int dynamic_set_parameter(AVCodecContext *avctx)
> +{
> +    AVDictionary *opts = NULL;
> +    int ret = 0;
> +    static int frame_number = 0;
> +    frame_number++;
> +    if (current_setting_number < setting_number &&
> +        frame_number == dynamic_setting[current_setting_number].frame_number)
> {
> +        AVDictionaryEntry *e = NULL;
> +        ret = str_to_dict(dynamic_setting[current_setting_number].optstr,
> &opts);
> +        if (ret < 0) {
> +            fprintf(stderr, "The dynamic parameter is wrong\n");
> +            goto fail;
> +        }
> +        /* Set common option. The dictionary will be freed and replaced
> +         * by a new one containing all options not found in common option
> list.
> +         * Then this new dictionary is used to set private option. */
> +        if ((ret = av_opt_set_dict(avctx, &opts)) < 0)
> +            goto fail;
> +        /* Set codec specific option */
> +        if ((ret = av_opt_set_dict(avctx->priv_data, &opts)) < 0)
> +            goto fail;
> +        /* There is no "framerate" option in commom option list. Use "-r" to
> set
> +         * framerate, which is compatible with ffmpeg commandline. The video
> is
> +         * assumed to be average frame rate, so set time_base to 1/framerate.
> */
> +        e = av_dict_get(opts, "r", NULL, 0);
> +        if (e) {
> +            avctx->framerate = av_d2q(atof(e->value), INT_MAX);
> +            encoder_ctx->time_base = av_inv_q(encoder_ctx->framerate);
> +        }
> +    }
> +fail:
> +    av_dict_free(&opts);
> +    return ret;
> +}
> +
> +static int get_format(AVCodecContext *avctx, const enum AVPixelFormat
> *pix_fmts)
> +{
> +    while (*pix_fmts != AV_PIX_FMT_NONE) {
> +        if (*pix_fmts == AV_PIX_FMT_QSV) {
> +            return AV_PIX_FMT_QSV;
> +        }
> +
> +        pix_fmts++;
> +    }
> +
> +    fprintf(stderr, "The QSV pixel format not offered in get_format()\n");
> +
> +    return AV_PIX_FMT_NONE;
> +}
> +
> +static int open_input_file(char *filename)
> +{
> +    int ret;
> +    const AVCodec *decoder = NULL;
> +    AVStream *video = NULL;
> +
> +    if ((ret = avformat_open_input(&ifmt_ctx, filename, NULL, NULL)) < 0) {
> +        fprintf(stderr, "Cannot open input file '%s', Error code: %s\n",
> +                filename, av_err2str(ret));
> +        return ret;
> +    }
> +
> +    if ((ret = avformat_find_stream_info(ifmt_ctx, NULL)) < 0) {
> +        fprintf(stderr, "Cannot find input stream information. Error code:
> %s\n",
> +                av_err2str(ret));
> +        return ret;
> +    }
> +
> +    ret = av_find_best_stream(ifmt_ctx, AVMEDIA_TYPE_VIDEO, -1, -1, NULL, 0);
> +    if (ret < 0) {
> +        fprintf(stderr, "Cannot find a video stream in the input file. "
> +                "Error code: %s\n", av_err2str(ret));
> +        return ret;
> +    }
> +    video_stream = ret;
> +    video = ifmt_ctx->streams[video_stream];
> +
> +    switch(video->codecpar->codec_id) {
> +    case AV_CODEC_ID_H264:
> +        decoder = avcodec_find_decoder_by_name("h264_qsv");
> +        break;
> +    case AV_CODEC_ID_HEVC:
> +        decoder = avcodec_find_decoder_by_name("hevc_qsv");
> +        break;
> +    case AV_CODEC_ID_VP9:
> +        decoder = avcodec_find_decoder_by_name("vp9_qsv");
> +        break;
> +    case AV_CODEC_ID_VP8:
> +        decoder = avcodec_find_decoder_by_name("vp8_qsv");
> +        break;
> +    case AV_CODEC_ID_AV1:
> +        decoder = avcodec_find_decoder_by_name("av1_qsv");
> +        break;
> +    case AV_CODEC_ID_MPEG2VIDEO:
> +        decoder = avcodec_find_decoder_by_name("mpeg2_qsv");
> +        break;
> +    case AV_CODEC_ID_MJPEG:
> +        decoder = avcodec_find_decoder_by_name("mjpeg_qsv");
> +        break;
> +    default:
> +        fprintf(stderr, "Codec is not supportted by qsv\n");
> +        return AVERROR(ENAVAIL);
> +    }
> +
> +    if (!(decoder_ctx = avcodec_alloc_context3(decoder)))
> +        return AVERROR(ENOMEM);
> +
> +    if ((ret = avcodec_parameters_to_context(decoder_ctx, video->codecpar)) <
> 0) {
> +        fprintf(stderr, "avcodec_parameters_to_context error. Error code:
> %s\n",
> +                av_err2str(ret));
> +        return ret;
> +    }
> +    decoder_ctx->framerate = av_guess_frame_rate(ifmt_ctx, video, NULL);
> +
> +    decoder_ctx->hw_device_ctx = av_buffer_ref(hw_device_ctx);
> +    if (!decoder_ctx->hw_device_ctx) {
> +        fprintf(stderr, "A hardware device reference create failed.\n");
> +        return AVERROR(ENOMEM);
> +    }
> +    decoder_ctx->get_format    = get_format;
> +    decoder_ctx->pkt_timebase = video->time_base;
> +    if ((ret = avcodec_open2(decoder_ctx, decoder, NULL)) < 0)
> +        fprintf(stderr, "Failed to open codec for decoding. Error code:
> %s\n",
> +                av_err2str(ret));
> +
> +    return ret;
> +}
> +
> +static int encode_write(AVPacket *enc_pkt, AVFrame *frame)
> +{
> +    int ret = 0;
> +
> +    av_packet_unref(enc_pkt);
> +
> +    if((ret = dynamic_set_parameter(encoder_ctx)) < 0) {
> +        fprintf(stderr, "Failed to set dynamic parameter. Error code: %s\n",
> +                av_err2str(ret));
> +        goto end;
> +    }
> +
> +    if ((ret = avcodec_send_frame(encoder_ctx, frame)) < 0) {
> +        fprintf(stderr, "Error during encoding. Error code: %s\n",
> av_err2str(ret));
> +        goto end;
> +    }
> +    while (1) {
> +        if (ret = avcodec_receive_packet(encoder_ctx, enc_pkt))
> +            break;
> +        enc_pkt->stream_index = 0;
> +        av_packet_rescale_ts(enc_pkt, encoder_ctx->time_base,
> +                             ofmt_ctx->streams[0]->time_base);
> +        if ((ret = av_interleaved_write_frame(ofmt_ctx, enc_pkt)) < 0) {
> +            fprintf(stderr, "Error during writing data to output file. "
> +                    "Error code: %s\n", av_err2str(ret));
> +            return ret;
> +        }
> +    }
> +
> +end:
> +    if (ret == AVERROR_EOF)
> +        return 0;
> +    ret = ((ret == AVERROR(EAGAIN)) ? 0:-1);
> +    return ret;
> +}
> +
> +static int dec_enc(AVPacket *pkt, const AVCodec *enc_codec, char *optstr)
> +{
> +    AVFrame *frame;
> +    int ret = 0;
> +
> +    ret = avcodec_send_packet(decoder_ctx, pkt);
> +    if (ret < 0) {
> +        fprintf(stderr, "Error during decoding. Error code: %s\n",
> av_err2str(ret));
> +        return ret;
> +    }
> +
> +    while (ret >= 0) {
> +        if (!(frame = av_frame_alloc()))
> +            return AVERROR(ENOMEM);
> +
> +        ret = avcodec_receive_frame(decoder_ctx, frame);
> +        if (ret == AVERROR(EAGAIN) || ret == AVERROR_EOF) {
> +            av_frame_free(&frame);
> +            return 0;
> +        } else if (ret < 0) {
> +            fprintf(stderr, "Error while decoding. Error code: %s\n",
> av_err2str(ret));
> +            goto fail;
> +        }
> +        if (!encoder_ctx->hw_frames_ctx) {
> +            AVDictionaryEntry *e = NULL;
> +            AVDictionary *opts = NULL;
> +            AVStream *ost;
> +            /* we need to ref hw_frames_ctx of decoder to initialize
> encoder's codec.
> +               Only after we get a decoded frame, can we obtain its
> hw_frames_ctx */
> +            encoder_ctx->hw_frames_ctx = av_buffer_ref(decoder_ctx-
> >hw_frames_ctx);
> +            if (!encoder_ctx->hw_frames_ctx) {
> +                ret = AVERROR(ENOMEM);
> +                goto fail;
> +            }
> +            /* set AVCodecContext Parameters for encoder, here we keep them
> stay
> +             * the same as decoder.
> +             */
> +            encoder_ctx->time_base = av_inv_q(decoder_ctx->framerate);
> +            encoder_ctx->pix_fmt   = AV_PIX_FMT_QSV;
> +            encoder_ctx->width     = decoder_ctx->width;
> +            encoder_ctx->height    = decoder_ctx->height;
> +            if ((ret = str_to_dict(optstr, &opts)) < 0) {
> +                fprintf(stderr, "Failed to set encoding parameter.\n");
> +                goto fail;
> +            }
> +            /* There is no "framerate" option in commom option list. Use "-r" 
> to
> +            * set framerate, which is compatible with ffmpeg commandline. The
> +            * video is assumed to be average frame rate, so set time_base to
> +            * 1/framerate. */
> +            e = av_dict_get(opts, "r", NULL, 0);
> +            if (e) {
> +                encoder_ctx->framerate = av_d2q(atof(e->value), INT_MAX);
> +                encoder_ctx->time_base = av_inv_q(encoder_ctx->framerate);
> +            }
> +            if ((ret = avcodec_open2(encoder_ctx, enc_codec, &opts)) < 0) {
> +                fprintf(stderr, "Failed to open encode codec. Error code:
> %s\n",
> +                        av_err2str(ret));
> +                av_dict_free(&opts);
> +                goto fail;
> +            }
> +            av_dict_free(&opts);
> +
> +            if (!(ost = avformat_new_stream(ofmt_ctx, enc_codec))) {
> +                fprintf(stderr, "Failed to allocate stream for output
> format.\n");
> +                ret = AVERROR(ENOMEM);
> +                goto fail;
> +            }
> +
> +            ost->time_base = encoder_ctx->time_base;
> +            ret = avcodec_parameters_from_context(ost->codecpar,
> encoder_ctx);
> +            if (ret < 0) {
> +                fprintf(stderr, "Failed to copy the stream parameters. "
> +                        "Error code: %s\n", av_err2str(ret));
> +                goto fail;
> +            }
> +
> +            /* write the stream header */
> +            if ((ret = avformat_write_header(ofmt_ctx, NULL)) < 0) {
> +                fprintf(stderr, "Error while writing stream header. "
> +                        "Error code: %s\n", av_err2str(ret));
> +                goto fail;
> +            }
> +        }
> +        frame->pts = av_rescale_q(frame->pts, decoder_ctx->pkt_timebase,
> +                                  encoder_ctx->time_base);
> +        if ((ret = encode_write(pkt, frame)) < 0)
> +            fprintf(stderr, "Error during encoding and writing.\n");
> +
> +fail:
> +        av_frame_free(&frame);
> +        if (ret < 0)
> +            return ret;
> +    }
> +    return 0;
> +}
> +
> +int main(int argc, char **argv)
> +{
> +    const AVCodec *enc_codec;
> +    int ret = 0;
> +    AVPacket *dec_pkt;
> +
> +    if (argc < 5 || (argc - 5) % 2) {
> +        av_log(NULL, AV_LOG_ERROR, "Usage: %s <input file> <encoder> <output
> file>"
> +               " <\"encoding option set 0\"> [<frame_number> <\"encoding
> options set 1\">]...\n", argv[0]);
> +        return 1;
> +    }
> +    setting_number = (argc - 5) / 2;
> +    dynamic_setting = av_malloc(setting_number * sizeof(*dynamic_setting));
> +    current_setting_number = 0;
> +    for (int i = 0; i < setting_number; i++) {
> +        dynamic_setting[i].frame_number = atoi(argv[i*2 + 5]);
> +        dynamic_setting[i].optstr = argv[i*2 + 6];
> +    }
> +
> +    ret = av_hwdevice_ctx_create(&hw_device_ctx, AV_HWDEVICE_TYPE_QSV, NULL,
> NULL, 0);
> +    if (ret < 0) {
> +        fprintf(stderr, "Failed to create a QSV device. Error code: %s\n",
> av_err2str(ret));
> +        goto end;
> +    }
> +
> +    dec_pkt = av_packet_alloc();
> +    if (!dec_pkt) {
> +        fprintf(stderr, "Failed to allocate decode packet\n");
> +        goto end;
> +    }
> +
> +    if ((ret = open_input_file(argv[1])) < 0)
> +        goto end;
> +
> +    if (!(enc_codec = avcodec_find_encoder_by_name(argv[2]))) {
> +        fprintf(stderr, "Could not find encoder '%s'\n", argv[2]);
> +        ret = -1;
> +        goto end;
> +    }
> +
> +    if ((ret = (avformat_alloc_output_context2(&ofmt_ctx, NULL, NULL,
> argv[3]))) < 0) {
> +        fprintf(stderr, "Failed to deduce output format from file extension.
> Error code: "
> +                "%s\n", av_err2str(ret));
> +        goto end;
> +    }
> +
> +    if (!(encoder_ctx = avcodec_alloc_context3(enc_codec))) {
> +        ret = AVERROR(ENOMEM);
> +        goto end;
> +    }
> +
> +    ret = avio_open(&ofmt_ctx->pb, argv[3], AVIO_FLAG_WRITE);
> +    if (ret < 0) {
> +        fprintf(stderr, "Cannot open output file. "
> +                "Error code: %s\n", av_err2str(ret));
> +        goto end;
> +    }
> +
> +    /* read all packets and only transcoding video */
> +    while (ret >= 0) {
> +        if ((ret = av_read_frame(ifmt_ctx, dec_pkt)) < 0)
> +            break;
> +
> +        if (video_stream == dec_pkt->stream_index)
> +            ret = dec_enc(dec_pkt, enc_codec, argv[4]);
> +
> +        av_packet_unref(dec_pkt);
> +    }
> +
> +    /* flush decoder */
> +    av_packet_unref(dec_pkt);
> +    if ((ret = dec_enc(dec_pkt, enc_codec, argv[4])) < 0) {
> +        fprintf(stderr, "Failed to flush decoder %s\n", av_err2str(ret));
> +        goto end;
> +    }
> +
> +    /* flush encoder */
> +    if ((ret = encode_write(dec_pkt, NULL)) < 0) {
> +        fprintf(stderr, "Failed to flush encoder %s\n", av_err2str(ret));
> +        goto end;
> +    }
> +
> +    /* write the trailer for output stream */
> +    if ((ret = av_write_trailer(ofmt_ctx)) < 0)
> +        fprintf(stderr, "Failed to write trailer %s\n", av_err2str(ret));
> +
> +end:
> +    avformat_close_input(&ifmt_ctx);
> +    avformat_close_input(&ofmt_ctx);
> +    avcodec_free_context(&decoder_ctx);
> +    avcodec_free_context(&encoder_ctx);
> +    av_buffer_unref(&hw_device_ctx);
> +    av_packet_free(&dec_pkt);
> +    av_freep(&dynamic_setting);
> +    return ret;
> +}


LGTM. Is there any comment for this example? I'll merge it if no comment /
objection. 

Thanks
Haihao