Examples with AVCodecContext org.bytedeco.ffmpeg.avcodec.AVCodecContext used on opensource projects

Example 1 with AVCodecContext

use of org.bytedeco.ffmpeg.avcodec.AVCodecContext in project cineast by vitrivr.

the class TechnicalVideoMetadataExtractor method extract.

/**
 * Extracts the technical video metadata from the specified path and returns a List of {@link MediaObjectMetadataDescriptor} objects (one for each metadata entry).
 *
 * @param objectId ID of the multimedia object for which metadata will be generated.
 * @param path     Path to the file for which metadata should be extracted.
 * @return List of {@link MediaObjectMetadataDescriptor}s or an empty list, if extracting metadata fails.
 */
@Override
public List<MediaObjectMetadataDescriptor> extract(String objectId, Path path) {
    final ArrayList<MediaObjectMetadataDescriptor> metadata = new ArrayList<>();
    if (!Files.exists(path)) {
        LOGGER.warn("File does not exist, returning empty metadata");
        return metadata;
    }
    /* we assume that everythign which can be handled by the ffmpegvideodecoder can also be handled here. Without this safety-guard, extraction will crash with a core-dump */
    if (!FFMpegVideoDecoder.supportedFiles.contains(MimeTypeHelper.getContentType(path.toString()))) {
        LOGGER.warn("File is not a video, returning empty metadata");
        return metadata;
    }
    /* Initialize the AVFormatContext. */
    final AVFormatContext pFormatContext = avformat.avformat_alloc_context();
    /* */
    if (avformat.avformat_open_input(pFormatContext, path.toString(), null, null) != 0) {
        LOGGER.error("Error while accessing file {}. Failed to obtain technical video metadata.", path.toString());
        return metadata;
    }
    /* Retrieve stream information. */
    if (avformat.avformat_find_stream_info(pFormatContext, (PointerPointer<?>) null) < 0) {
        LOGGER.error("Error, Ccouldn't find stream information. Failed to obtain technical video metadata.");
        return metadata;
    }
    final AVCodec codec = avcodec.av_codec_iterate(new Pointer());
    final int videoStreamIdx = avformat.av_find_best_stream(pFormatContext, avutil.AVMEDIA_TYPE_VIDEO, -1, -1, codec, 0);
    final AVStream videoStream = pFormatContext.streams(videoStreamIdx);
    final AVRational timebase = videoStream.time_base();
    /* Allocate new codec-context for codec returned by av_find_best_stream(). */
    final AVCodecContext videoCodecContext = avcodec.avcodec_alloc_context3(codec);
    avcodec.avcodec_parameters_to_context(videoCodecContext, videoStream.codecpar());
    /* Open the code context. */
    if (avcodec.avcodec_open2(videoCodecContext, codec, (AVDictionary) null) < 0) {
        LOGGER.error("Error, Could not open video codec.  Failed to obtain technical video metadata.");
        return metadata;
    }
    /* Extract and add the video metadata to the list. */
    metadata.add(new MediaObjectMetadataDescriptor(objectId, this.domain(), KEY_VIDEO_FPS, ((float) videoStream.avg_frame_rate().num() / (float) videoStream.avg_frame_rate().den()), false));
    metadata.add(new MediaObjectMetadataDescriptor(objectId, this.domain(), KEY_VIDEO_DURATION, Math.floorDiv(videoStream.duration() * timebase.num() * 1000, timebase.den()), false));
    metadata.add(new MediaObjectMetadataDescriptor(objectId, this.domain(), KEY_VIDEO_WIDTH, videoCodecContext.width(), false));
    metadata.add(new MediaObjectMetadataDescriptor(objectId, this.domain(), KEY_VIDEO_HEIGHT, videoCodecContext.height(), false));
    /* Closes all the resources. */
    avcodec.avcodec_free_context(videoCodecContext);
    avformat.avformat_close_input(pFormatContext);
    /* Return list of results. */
    return metadata;
}