KShare/recording/encoders/encoder.cpp

#include "encoder.hpp"

#include <settings.hpp>
extern "C" {
#include <libavutil/imgutils.h>
#include <libavutil/opt.h>
}

inline void throwAVErr(int ret, std::string section) {
    char err[AV_ERROR_MAX_STRING_SIZE];
    av_make_error_string(err, AV_ERROR_MAX_STRING_SIZE, ret);
    std::string newString(err);
    throw std::runtime_error("Error during: " + section + ": " + newString);
}

#define OR_DEF(s, e1, e2) s ? s->e1 : e2

Encoder::Encoder(QString &targetFile, QSize res, CodecSettings *settings) {
    int ret;
    // Format
    ret = avformat_alloc_output_context2(&fc, NULL, NULL, targetFile.toLocal8Bit().constData());
    if (ret < 0) throwAVErr(ret, "format alloc");

    // Stream
    out->st = avformat_new_stream(fc, NULL);
    if (!out->st) throw std::runtime_error("Unable to allocate video context");
    out->st->id = fc->nb_streams - 1;
    if (fc->oformat->flags & AVFMT_GLOBALHEADER) fc->flags |= AV_CODEC_FLAG_GLOBAL_HEADER;
    av_dump_format(fc, 0, targetFile.toLocal8Bit().constData(), 1);

    // Codec
    if (!fc->oformat->video_codec) throw std::runtime_error("Video codec not found");
    codec = avcodec_find_encoder(fc->oformat->video_codec);
    if (!codec) throw std::runtime_error("Video codec not found");
    out->enc = avcodec_alloc_context3(codec);
    if (!out->enc) throw std::runtime_error("Unable to allocate video context");

    int fps = settings::settings().value("recording/framerate", 30).toInt();

    out->enc->codec_id = codec->id;
    out->enc->codec = codec;

    out->enc->bit_rate = OR_DEF(settings, bitrate, 400000);
    out->enc->width = res.width() % 2 ? res.width() - 1 : res.width();
    out->enc->height = res.height() % 2 ? res.height() - 1 : res.height();
    size = QSize(out->enc->width, out->enc->height);
    out->st->time_base = { 1, fps };
    out->enc->time_base = out->st->time_base;

    out->enc->gop_size = OR_DEF(settings, gopSize, 12);
    out->enc->pix_fmt = AV_PIX_FMT_YUV420P; // blaze it
    AVDictionary *dict = NULL;
    if (out->enc->codec_id == AV_CODEC_ID_GIF)
        out->enc->pix_fmt = AV_PIX_FMT_RGB8;
    else if (out->enc->codec_id == AV_CODEC_ID_H264 || out->enc->codec_id == AV_CODEC_ID_H265) {
        av_dict_set(&dict, "preset", settings ? settings->h264Profile.toLocal8Bit().constData() : "medium", 0);
        av_dict_set_int(&dict, "crf", OR_DEF(settings, h264Crf, 12), 0);
    } else if (out->enc->codec_id == AV_CODEC_ID_VP8 || out->enc->codec_id == AV_CODEC_ID_VP9)
        av_dict_set_int(&dict, "lossless", OR_DEF(settings, vp9Lossless, false), 0);


    ret = avcodec_open2(out->enc, codec, &dict);
    av_dict_free(&dict);
    if (ret < 0) throwAVErr(ret, "codec open");
    if (codec->capabilities & AV_CODEC_CAP_DR1) avcodec_align_dimensions(out->enc, &out->enc->width, &out->enc->height);

    ret = avcodec_parameters_from_context(out->st->codecpar, out->enc);
    if (ret < 0) throwAVErr(ret, "stream opt copy");

    // Frames
    out->frame = av_frame_alloc();
    if (!out->frame) {
        throw std::runtime_error("frame alloc");
    }
    out->frame->format = out->enc->pix_fmt;
    out->frame->width = out->enc->width;
    out->frame->height = out->enc->height;
    ret = av_frame_get_buffer(out->frame, 32);
    if (ret < 0) throwAVErr(ret, "frame buffer alloc");

    // Writer
    ret = avio_open(&fc->pb, targetFile.toLocal8Bit().constData(), AVIO_FLAG_WRITE);
    if (ret < 0) throwAVErr(ret, "writer open");
    ret = avformat_write_header(fc, NULL);
    if (ret < 0) throwAVErr(ret, "write header");

    success = true;
}

void Encoder::setFrameRGB(QImage img) {
    uint8_t *rgb = (uint8_t *)img.bits();
    int ret = av_frame_make_writable(out->frame);
    if (ret < 0) throwAVErr(ret, "setFrameRGB");
    int lineSize[1] = { img.bytesPerLine() };
    out->sws = sws_getCachedContext(out->sws, out->enc->width, out->enc->height, AV_PIX_FMT_RGB24, out->enc->width,
                                    out->enc->height, (AVPixelFormat)out->frame->format, 0, 0, 0, 0);
    sws_scale(out->sws, (const uint8_t *const *)&rgb, lineSize, 0, out->enc->height, out->frame->data, out->frame->linesize);
    out->frame->pts = out->nextPts++;
}

Encoder::~Encoder() {
    end();
}

bool Encoder::addFrame(QImage frm) {
    if (!success) return false;
    if (frm.size() != size) frm = frm.copy(QRect(QPoint(0, 0), size));
    if (frm.format() != QImage::Format_RGB888) frm = frm.convertToFormat(QImage::Format_RGB888);
    setFrameRGB(frm);
    AVPacket pkt;
    pkt.size = 0;
    pkt.data = NULL;
    av_init_packet(&pkt);
    int ret = avcodec_send_frame(out->enc, out->frame);
    if (ret == AVERROR(EAGAIN)) {
        do {
            ret = avcodec_receive_packet(out->enc, &pkt);
            if (ret < 0) {
                if (ret != AVERROR(EAGAIN))
                    throwAVErr(ret, "receive packet");
                else
                    break;
            }
            av_packet_rescale_ts(&pkt, out->enc->time_base, out->st->time_base);
            pkt.stream_index = out->st->index;
            ret = av_interleaved_write_frame(fc, &pkt);
        } while (ret >= 0);
        if (ret < 0 && ret != AVERROR(EAGAIN)) {
            av_packet_unref(&pkt);
            throwAVErr(ret, "send frame");
        }
    }
    av_packet_unref(&pkt);
    if (ret < 0 && ret != AVERROR(EAGAIN)) throwAVErr(ret, "send frame");
    return true;
}

bool Encoder::isRunning() {
    return success;
}

bool Encoder::end() {
    if (ended) return false;
    ended = true;
    if (!success) {
        goto cleanup;
    }
    int ret;
    AVPacket pkt;
    pkt.size = 0;
    pkt.data = NULL;
    av_init_packet(&pkt);
    do {
        ret = avcodec_receive_packet(out->enc, &pkt);
        if (ret < 0) break;
        av_packet_rescale_ts(&pkt, out->enc->time_base, out->st->time_base);
        pkt.stream_index = out->st->index;
        av_interleaved_write_frame(fc, &pkt);
    } while (ret >= 0);
    av_write_trailer(fc);
cleanup:
    avcodec_free_context(&out->enc);
    av_frame_free(&out->frame);
    sws_freeContext(out->sws);
    delete out;
    if (!(fc->oformat->flags & AVFMT_NOFILE)) //
        avio_closep(&fc->pb);
    avformat_free_context(fc);
    return success;
}