How to Disable Buffering on a Stream

How to disable buffering on a stream?

For file streams, you can use pubsetbuf for that :

std::ifstream f;
f.rdbuf()->pubsetbuf(0, 0);
f.open("test");

Explanation

The C++ standard says the following about the effect of setbuf (and thus pubsetbuf) for file streams :

If setbuf(0,0) is called on a stream before any I/O has occurred on that stream, the stream
becomes unbuffered. Otherwise the results are implementation-defined. “Unbuffered” means that
pbase() and pptr() always return null and output to the file should appear as soon as possible.

The first sentence guarantees that the above code makes the stream unbuffered. Note that some compilers (eg. gcc) see opening a file as an I/O operation on the stream, so pubsetbuf should be called before opening the file (as above).

The last sentence, however, seems to imply that that would only be for output, and not for input. I'm not sure if that was an oversight, or whether that was intended. Consulting your compiler documentation might be useful. For gcc eg., both input and output are made unbuffered (ref. GNU C++ Library Manual - Stream Buffers).

Disabling Chrome buffering when streaming text data

Add X-Content-Type-Options: nosniff to your headers and let me know how it goes for you.

According to Mozilla Docs:

The X-Content-Type-Options response HTTP header is a marker used by
the server to indicate that the MIME types advertised in the
Content-Type headers should not be changed and be followed. This
allows to opt-out of MIME type sniffing, or, in other words, it is a
way to say that the webmasters knew what they were doing.

Qt::QMediaPlayer: how to disable frame buffering to reduce the RTSP streaming delay or latency?

Finally!

After a lots of seaching and trying, I finally found a kind of weird way to fix this issue:

Using 'setPlaybackRate()' to set playback rate to zero, other then a
value bigger than the real fps to prevent the RTSP buffering.

void AmbaRemoteCam::slot_btnConnectRtsp_Clicked()
{
    m_player->setMedia(QUrl(m_mediaUrl->text()));
    m_player->setPlaybackRate(0);
    m_player->play();
}

Nobody would think of using this method to prevent the RTSP buffering.

Hope next version of QMediaPlayer has a more humane interface to fix this issue.

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