DirectShow记录问题-fps [英] DirectShow Record Problem - fps

问题描述

我只是创建一个简单的图形来记录来自源过滤器的视频：

I just create simple graph to record video from a source Filter:

SourceFilter ---> Muxer ---> FileWriter

我能够将来自SourceFilter的视频保存到本地磁盘。

I can able to save video which come from SourceFilter to my local disk.

But when i try to play the recorded video, it play in "slow motion" :-).

确定存在fps（帧每秒）问题。我该如何解决？有什么想法吗？

It is sure that there is fps (frame persecond) problem. How can i fix it? any ideas?

PS：

要检查我的SourceFilter是否提供fps fps，我只需创建另一个图：

To check if my SourceFilter give righ fps i simply create another graph:

SourceFilter ---> Video Decoder ---> Video Renderer

并以正确的速度（fps）播放

and it plays at right speed (fps)

更多详细信息：

SourceFilter(*.mp4 file format) ---> Avi Mux Filter ---> File writer Filter

此记录但fps错误。

This record but in wrong fps.

当我尝试gdcl MP4 Mux（可以在这里看到它）我成功获得了正确的fps。

When I try gdcl MP4 Mux ( can see it here ) i successfully get right fps.

SourceFilter(*.mp4 file format) ---> GDCL MPEG 4 Mux Filter ---> File writer Filter

其他情况

SourceFilter( *.h264 file format) ---> Avi Mux Filter ---> File writer Filter
SourceFilter( *.h264 file format) ---> GDCL MPEG 4 Mux Filter---> File writer Filter

它记录但记录了文件无法播放。

实际上我不想解码任何东西...只需将原始编码的视频帧（mp4，h264）写入文件中即可。不需要带视频的合成音频...为什么需要Mux？

And actually i do not want decode anything...Just write the originally encoded video frames(mp4,h264) into file. And also i may not need syn audio with video...Why need Mux?

我理想的过滤器应为：

SourceFilter(whatever format) ---> File writer

推荐答案

Ralf的评论可能是正确的。 AVI文件格式没有每帧的时间戳，只有平均帧速率。因此，当帧到达时，多路复用器必须决定是将该帧放置在下一个插槽中，还是插入丢帧标记，然后将帧放置在插槽中。如果源过滤器的时间戳与媒体类型的帧速率不匹配，那么您将获得这种效果。

Ralf's comment is probably right. The AVI file format doesn't have per-frame timestamps, just an average frame rate. So when a frame arrives, the mux has to decide whether to place this frame in the next "slot", or insert a "dropped frame" marker and put the frame in the slot after. If the source filter's timestamps don't match the media type's frame rate, then you will get this effect.

您可以将视频基本流保存到文件中，但可以使用转储过滤器示例，而不是文件编写器。文件编写器有一个特殊的协议，允许多路复用器随机访问文件（使用时间戳作为文件偏移量）。您只想将数据另存为流，然后使用转储示例。

You can save your video elementary stream to a file, but use the Dump filter example, not the file writer. The file writer has a special protocol to allow multiplexors random access to the file (using the timestamps as file offsets). You want to just save the data as a stream, and the Dump example does that.

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