Implement class audio/video metadata fetch using libav.

avdecoder.cpp

@@ -0,0 +1,214 @@
+#include "avdecoder.h"
+
+#include <QBuffer>
+#include <QSettings>
+
+AVDecoder::AVDecoder() :
+    pFormatCtx(NULL)
+{
+}
+
+bool AVDecoder::open(const QString filename)
+{
+    if(avformat_open_input(&pFormatCtx, filename.toStdString().c_str(), NULL, NULL) != 0) {
+        return false;
+    }
+
+    if(avformat_find_stream_info(pFormatCtx, NULL) < 0) {
+        avformat_close_input(&pFormatCtx);
+        return false;
+    }
+
+    return true;
+}
+
+void AVDecoder::getAudioMetadata(metadata_t &metadata)
+{
+    AVDictionaryEntry *entry;
+    AVDictionary* file_metadata = pFormatCtx->metadata;
+
+    if((entry = av_dict_get(file_metadata, "artist", NULL, 0)) != NULL) {
+        metadata.data.music.artist = strdup(entry->value);
+    } else {
+        metadata.data.music.artist = strdup("");
+    }
+
+    if((entry = av_dict_get(file_metadata, "album", NULL, 0)) != NULL) {
+        metadata.data.music.album = strdup(entry->value);
+    } else {
+        metadata.data.music.album = strdup("");
+    }
+
+    if((entry = av_dict_get(file_metadata, "title", NULL, 0)) != NULL) {
+        metadata.data.music.title = strdup(entry->value);
+    } else {
+        metadata.data.music.title = strdup("");
+    }
+
+    av_dict_free(&file_metadata);
+}
+
+void AVDecoder::getVideoMetadata(metadata_t &metadata)
+{
+    AVDictionaryEntry *entry;
+    AVDictionary* file_metadata = pFormatCtx->metadata;
+
+    if((entry = av_dict_get(file_metadata, "copyright", NULL, 0)) != NULL) {
+        metadata.data.video.copyright = strdup(entry->value);
+    } else {
+        metadata.data.video.copyright = strdup("");
+    }
+
+    if((entry = av_dict_get(file_metadata, "comments", NULL, 0)) != NULL) {
+        metadata.data.video.explanation = strdup(entry->value);
+    } else {
+        metadata.data.video.explanation = strdup("");
+    }
+
+    if((entry = av_dict_get(file_metadata, "title", NULL, 0)) != NULL) {
+        metadata.data.video.title = strdup(entry->value);
+    } else {
+        metadata.data.video.title = strdup("");
+    }
+
+    av_dict_free(&file_metadata);
+}
+
+QByteArray AVDecoder::getAudioThumbnail(int width, int height)
+{
+    QByteArray data;
+    for (uint i = 0; i < pFormatCtx->nb_streams; i++) {
+        if(pFormatCtx->streams[i]->disposition & AV_DISPOSITION_ATTACHED_PIC) {
+            AVPacket pkt = pFormatCtx->streams[i]->attached_pic;
+
+            QBuffer imgbuffer(&data);
+            imgbuffer.open(QIODevice::WriteOnly);
+            QImage img = QImage::fromData(QByteArray((const char *)pkt.data, pkt.size));
+            QImage result = img.scaled(width, height, Qt::KeepAspectRatio, Qt::SmoothTransformation);
+            result.save(&imgbuffer, "JPEG");
+            av_free_packet(&pkt);
+            break;
+        }
+    }
+    return data;
+}
+
+void AVDecoder::AVFrameToQImage(AVFrame &frame, QImage &image, int width, int height)
+{
+    quint8 *src = frame.data[0];
+
+    for (int y = 0; y < height; y++) {
+        QRgb *scanLine = (QRgb *)image.scanLine(y);
+
+        for (int x = 0; x < width; x++) {
+            scanLine[x] = qRgb(src[3*x], src[3*x+1], src[3*x+2]);
+        }
+        src += frame.linesize[0];
+    }
+}
+
+AVFrame *AVDecoder::getDecodedFrame(AVCodecContext *pCodecCtx, int stream_index)
+{
+    AVFrame *pFrame = avcodec_alloc_frame();
+
+    AVPacket packet;
+    int frame_finished = 0;
+
+    while(!frame_finished && av_read_frame(pFormatCtx, &packet)>=0) {
+        if(packet.stream_index == stream_index) {
+            avcodec_decode_video2(pCodecCtx, pFrame, &frame_finished, &packet);
+        }
+        av_free_packet(&packet);
+    }
+
+    if(frame_finished) {
+        return pFrame;
+    } else {
+        av_free(pFrame);
+        return NULL;
+    }
+}
+
+QByteArray AVDecoder::getVideoThumbnail(int width, int height)
+{
+    QByteArray data;
+    int stream_index;
+    AVFrame *pFrame;
+    AVCodec *codec = NULL;
+    AVCodecContext *pCodecCtx = NULL;
+
+    int percentage = QSettings().value("videoThumbnailSeekPercentage", 30).toInt();
+
+    if((stream_index = av_find_best_stream(pFormatCtx, AVMEDIA_TYPE_VIDEO, -1, -1, &codec, 0)) < 0) {
+        return data;
+    }
+
+    pCodecCtx = pFormatCtx->streams[stream_index]->codec;
+
+    if(avcodec_open2(pCodecCtx, codec, NULL) < 0) {
+        avcodec_close(pCodecCtx);
+        return data;
+    }
+
+    if(av_seek_frame(pFormatCtx, stream_index, pFormatCtx->duration * percentage / 100, 0) < 0) {
+        avcodec_close(pCodecCtx);
+        return data;
+    }
+
+    if((pFrame = getDecodedFrame(pCodecCtx, stream_index)) == NULL) {
+        avcodec_close(pCodecCtx);
+        return data;
+    }
+
+    AVFrame *pFrameRGB = avcodec_alloc_frame();
+
+    int numBytes = avpicture_get_size(PIX_FMT_RGB24, pCodecCtx->width, pCodecCtx->height);
+    uint8_t *buffer = (uint8_t *)av_malloc(numBytes * sizeof(uint8_t));
+
+    avpicture_fill((AVPicture *)pFrameRGB, buffer, PIX_FMT_RGB24, pCodecCtx->width, pCodecCtx->height);
+
+    SwsContext *sws_ctx = sws_getContext(
+        pCodecCtx->width,
+        pCodecCtx->height,
+        pCodecCtx->pix_fmt,
+        pCodecCtx->width,
+        pCodecCtx->height,
+        PIX_FMT_RGB24,
+        SWS_BILINEAR,
+        NULL,
+        NULL,
+        NULL
+    );
+
+    QImage img(pCodecCtx->width, pCodecCtx->height, QImage::Format_RGB32);
+
+    sws_scale(
+        sws_ctx,
+        (uint8_t const * const *)pFrame->data,
+        pFrame->linesize,
+        0,
+        pCodecCtx->height,
+        pFrameRGB->data,
+        pFrameRGB->linesize
+    );
+
+    AVFrameToQImage(*pFrame, img, pCodecCtx->width, pCodecCtx->height);
+
+    QBuffer imgbuffer(&data);
+    imgbuffer.open(QIODevice::WriteOnly);
+    QImage result = img.scaled(width, height, Qt::KeepAspectRatio, Qt::SmoothTransformation);
+    result.save(&imgbuffer, "JPEG");
+
+    av_free(buffer);
+    av_free(pFrameRGB);
+    av_free(pFrame);
+
+    avcodec_close(pCodecCtx);
+
+    return data;
+}
+
+void AVDecoder::close()
+{
+    avformat_close_input(&pFormatCtx);
+}