To process specialized file formats (such as video) in Hadoop, you'd have to write a custom InputFormat and RecordReader that understands how to turn a video file into splits (the InputFormat) and then read splits into values (the RecordReader).在Hadoop要处理的专用文件格式(如视频),你就必须写一个自定义的InputFormat和RecordReader,了解如何将一个视频文件分割(InputFormat),然后读值(RecordReader)分裂成。 This is a non-trivial task and requires some intermediate knowledge of how Hadoop handles the splitting of data.这是一个不平凡的任务和Hadoop的处理分割的数据需要一些中间的知识。 I highly recommend Tom White's Hadoop the Definitive Guide book by O'Reilly as well as the videos on http://www.cloudera.com .我强烈建议汤姆白色的Hadoop权威指南书由O'Reilly和视频http://www.cloudera.com 。 (Full disclosure: I work for Cloudera.) (披露:我工作的Cloudera的。)
Keep in mind that video formats are generally compressed which gets even more complicated because InputSplits (created by an InputFormat) are simple byte offsets into the file (normally).请记住,一般都是压缩的视频格式变得更加复杂,因为InputSplits创建一个InputFormat是简单的字节偏移量到文件中(通常情况下)。 Start withhttp://hadoop.apache.org/common/docs/current/api/org/apache/hadoop/mapred/InputFormat.html从与http://hadoop.apache.org/common/docs/current/api/org/apache/hadoop/mapred/InputFormat.html开始
To summarize: InputFormat knows how to generate a list of InputSplit objects that are (usually) between 64MB and 128MB and do NOT respect the notion of frames.总结:InputFormat知道如何生成的列表InputSplit对象(通常情况下),64MB和128MB之间, 不尊重的概念框架。 The RecordReader then is used to read frames out of a InputSplit to create value objects that the map reduce job can process. “的RecordReader然后是用于读取帧一的InputSplit,以创建的Map Reduce作业可以处理的值对象。 If you want to generate video output you'll also need to write a custom OutputFormat.如果你想生成视频输出,您还需要编写一个自定义的OutputFormat。
Hope this helps.希望这会有所帮助。