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There are more advanced options, depending on your h.264 encoder.
For example the TI h.264 encoder supports a couple of features,
Temporal Scalability and Chain Free P Frame encoding. <br>
<a
href="http://processors.wiki.ti.com/index.php/H.264_DM36x_Ver_2.0_Codec#Scalable_video_coding_.E2.80.93_Temporal">http://processors.wiki.ti.com/index.php/H.264_DM36x_Ver_2.0_Codec#Scalable_video_coding_.E2.80.93_Temporal</a><br>
<a
href="http://processors.wiki.ti.com/index.php/H.264_DM36x_Ver_2.0_Codec#Chain_Free_P_frame_encoding">http://processors.wiki.ti.com/index.php/H.264_DM36x_Ver_2.0_Codec#Chain_Free_P_frame_encoding</a><br>
<br>
Both of which allow one to transmit and decode some subset of the
encoded bit stream, usually on some even multiple of the key frame
frequency. <br>
<br>
Both of these methods requires you to know or at least discover some
pretty detailed information about the bit stream you are
retransmitting but it can be done. <br>
<br>
Matt S. <br>
<br>
<div class="moz-cite-prefix">On 10/14/2012 6:24 AM, Jeff Shanab
wrote:<br>
</div>
<blockquote
cite="mid:615FD77639372542BF647F5EBAA2DBC22521DC92@IL-BOL-EXCH01.smartwire.com"
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<div style="">In the simplest case, H264 defines a protocol that
starts with a key frame and has a succession of difference
frames that are much smaller. ie the 24KByte key frame has all
the information needed to draw the whole frame and the 1Kbyte
diff frame has only the changes needed to update the key frame
to the new display frame. <br>
The first difference frame depends on the key frame and each
diff frame depends on the key frame and the changes made by
all the proceeding diff frames.<br>
<br>
One trick would be to have a key frame per second and send and
display only keyframes.
<br>
But since the keyframes are big you can expect at most a 60%
reduction on 30fps video.<br>
<br>
Anything else is transcoding. Decode the video at the source
fps and re-encode at the fps you want to display.<br>
This can be done in software with libavcodec, but it takes
CPU!<br>
This also would let you reduce the resolution, sometimes the
client is not viewing it at full resolution and that effects
bandwidth considerably.<br>
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<div style="direction: ltr;" id="divRpF561432"><font
color="#000000" size="2" face="Tahoma"><b>From:</b>
<a class="moz-txt-link-abbreviated" href="mailto:live-devel-bounces@ns.live555.com">live-devel-bounces@ns.live555.com</a>
[<a class="moz-txt-link-abbreviated" href="mailto:live-devel-bounces@ns.live555.com">live-devel-bounces@ns.live555.com</a>] on behalf of Tarun
Batra [<a class="moz-txt-link-abbreviated" href="mailto:tbatra18@gmail.com">tbatra18@gmail.com</a>]<br>
<b>Sent:</b> Thursday, October 11, 2012 10:20 AM<br>
<b>To:</b> <a class="moz-txt-link-abbreviated" href="mailto:live-devel@ns.live555.com">live-devel@ns.live555.com</a><br>
<b>Subject:</b> [Live-devel] How to re transmit<br>
</font><br>
</div>
<div>
<div>Hello Sir,</div>
<div><br>
</div>
<div> I have implemented “testOnDemandRTSPServer” on my
machine which receives h264 transport stream from my
streamer application.</div>
<div><br>
</div>
<div> Is there any way to re transmit this received
stream from streamer, to my RTSP clients with different
fame rates? As some of my RTSP clients do not have
sufficient bandwidth to receive stream with high frame
rate. My streamer uses MPEG1or2VideoStreamDiscreteFramer
to stream a video from digital camera.</div>
<div><br>
</div>
</div>
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<br>
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</pre>
</blockquote>
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