c# - FFmpeg av_interleaved_write_frame 缓冲

Question

嗨，我正在使用 FFmpeg Autogen C#。当我使用 mkv 输出作为文件并使用 h264 rtsp 流作为输入时，一切正常。编解码器是 libx264

  ffmpeg.avio_open(&container->pb, filename, 2),
  fmpeg.avformat_write_header(container, null)
  ffmpeg.av_read_frame(inputContainer, &pkt)
  ffmpeg.av_interleaved_write_frame(container, &pkt).

Mkv 文件输出工作完美。
但是当我试图打开 AVIOContext 到缓冲区时

ffmpeg.avio_alloc_context(avio_ctx_buffer, 32768, 1, &bd, null, write, seek)

搜索功能

unsafe long seek(void* opaque, long offset, int whence)
    {
        buffer_data* bd = (buffer_data*)opaque;
        switch (whence)
        {
            case 0:
                bd->ptr = bd->buf + offset;
                return (long)bd->ptr;
            case 1:
                bd->ptr += offset;
                break;
            case 2:
                bd->ptr = (bd->buf + bd->size) + offset;
                return (long)bd->ptr;
            case 65536:
                return bd->size;
            default:
                return -1;
        }
        return 1;
    }

写函数

 unsafe int write(void* opaque, byte* buf, int buf_size)
        {

            buffer_data* bd = (buffer_data*)opaque;
            while ((ulong)buf_size > bd->room)
            {
                long offset = bd->ptr - bd->buf;
                bd->buf = (byte*)ffmpeg.av_realloc_f(bd->buf, 2, (ulong)bd->size);
                if (bd->buf == null)
                    return ffmpeg.AVERROR(ffmpeg.ENOMEM);
                bd->size *= 2;
                bd->ptr = bd->buf + offset;
                bd->room = (ulong)(bd->size - offset);
            } 
            memcpy((IntPtr)bd->ptr, (IntPtr)buf, (UIntPtr)buf_size); 
            bd->ptr += buf_size;
            bd->room -= (ulong)buf_size;
            byte[] b = new byte[buf_size];
            Marshal.Copy((IntPtr)buf, b, 0, buf_size);
            using (var fs = new FileStream(@"D:\file1.mkv", FileMode.Append, FileAccess.Write, FileShare.ReadWrite))
            {
                using (BinaryWriter writer = new BinaryWriter(fs))
                {
                    writer.Write(b);
                }

            }
            return buf_size;
        }

缓冲数据

public unsafe struct buffer_data
        {
            public byte* buf;
            public long size;
            public byte* ptr;
            public ulong room; ///< size left in the buffer
        };

我得到的结果是 1 秒 mkv 视频(它的大小增加但 vlc 播放器无法播放)。另外请注意，写入文件只是为了测试我试图将 mkv 数据保存在缓冲区中。谢谢!!!。如果缺少smth请评论我会添加

Answer 1

抱歉打扰:) ,Silli 错误

 switch (whence)
        {
            case 0:
                bd->ptr = (bd->buf + bd->size) + offset;
                return (long)bd->ptr;
            case 1:
                bd->ptr += offset;
                break;
            case 2:
                bd->ptr = bd->buf + offset;
                return (long)bd->ptr;
            case 65535:
                return bd->size;
            default:
                return -1;
        }