5
我的视频设置的格式布局如下:FFmpeg的“movflags”>“的fastStart”导致无效MP4文件写到
AVOutputFormat* outputFormat = ffmpeg.av_guess_format(null, "output.mp4", null);
AVCodec* videoCodec = ffmpeg.avcodec_find_encoder(outputFormat->video_codec);
AVFormatContext* formatContext = ffmpeg.avformat_alloc_context();
formatContext->oformat = outputFormat;
formatContext->video_codec_id = videoCodec->id;
ffmpeg.avformat_new_stream(formatContext, videoCodec);
这是我如何设置的编解码器上下文:
AVCodecContext* codecContext = ffmpeg.avcodec_alloc_context3(videoCodec);
codecContext->bit_rate = 400000;
codecContext->width = 1280;
codecContext->height = 720;
codecContext->gop_size = 12;
codecContext->max_b_frames = 1;
codecContext->pix_fmt = videoCodec->pix_fmts[0];
codecContext->codec_id = videoCodec->id;
codecContext->codec_type = videoCodec->type;
codecContext->time_base = new AVRational
{
num = 1,
den = 30
};
我用下面的代码来设置 “movflags”>为视频的标题 “的fastStart” 选项:
AVDictionary* options = null;
int result = ffmpeg.av_dict_set(&options, "movflags", "faststart", 0);
int writeHeaderResult = ffmpeg.avformat_write_header(formatContext, &options);
该文件被打开和首标被写为如下:
if ((formatContext->oformat->flags & ffmpeg.AVFMT_NOFILE) == 0)
{
int ioOptionResult = ffmpeg.avio_open(&formatContext->pb, "output.mp4", ffmpeg.AVIO_FLAG_WRITE);
}
int writeHeaderResult = ffmpeg.avformat_write_header(formatContext, &options);
在此之后,我写每个视频帧如下:
outputFrame->pts = frameIndex;
packet.flags |= ffmpeg.AV_PKT_FLAG_KEY;
packet.pts = frameIndex;
packet.dts = frameIndex;
int encodedFrame = 0;
int encodeVideoResult = ffmpeg.avcodec_encode_video2(codecContext, &packet, outputFrame, &encodedFrame);
if (encodedFrame != 0)
{
packet.pts = ffmpeg.av_rescale_q(packet.pts, codecContext->time_base, m_videoStream->time_base);
packet.dts = ffmpeg.av_rescale_q(packet.dts, codecContext->time_base, m_videoStream->time_base);
packet.stream_index = m_videoStream->index;
if (codecContext->coded_frame->key_frame > 0)
{
packet.flags |= ffmpeg.AV_PKT_FLAG_KEY;
}
int writeFrameResult = ffmpeg.av_interleaved_write_frame(formatContext, &packet);
}
之后,我写拖车:
int writeTrailerResult = ffmpeg.av_write_trailer(formatContext);
文件完成写入,所有内容都会关闭并正确释放。但是,MP4文件是无法播放的(甚至VLC无法播放它)。 AtomicParsley.exe不会显示有关该文件的任何信息。
用于AUTOGEN库DLL是:
avcodec-56.dll
avdevice-56.dll
avfilter-5.dll
avformat-56.dll
avutil-54.dll
postproc-53.dll
swresample-1.dll
swscale-3.dll
如何创建formatContext? – szatmary
更新的问题。 – williamtroup
io环境在哪里?数据在哪里写入?如果您正在使用流媒体io(如粗壮),则无法快速启动该文件,因为查找不适用于流。 – szatmary