<html> <head> <meta http-equiv="Content-Type" content="text/html; charset=gb2312"> <style type="text/css" style="display:none;"> P {margin-top:0;margin-bottom:0;} </style> </head> <body dir="ltr"> <div style="color: rgb(0, 0, 0); font-family: Calibri,Helvetica,sans-serif; font-size: 12pt;"> Ciao, <span style="display: inline !important; background-color: rgb(255, 255, 255); font-size: 11pt; font-size-adjust: none">Antonio</span><br> </div> <div style="color: rgb(0, 0, 0); font-family: Calibri,Helvetica,sans-serif; font-size: 12pt;"> <br> </div> <div style="color: rgb(0, 0, 0); font-family: Calibri,Helvetica,sans-serif; font-size: 12pt;"> Thanks for efforts to explain more clear of my perspectives. </div> <div style="color: rgb(0, 0, 0); font-family: Calibri,Helvetica,sans-serif; font-size: 12pt;"> <br> </div> <div style="color: rgb(0, 0, 0); font-family: Calibri,Helvetica,sans-serif; font-size: 12pt;"> Per your test results, does that mean gstreamer can produce a bitmap stream file through a video stream, but it does not have capability vice visa?</div> <div style="color: rgb(0, 0, 0); font-family: Calibri,Helvetica,sans-serif; font-size: 12pt;"> <font color="#001000" face="arial" size="2" style="background-color: rgb(255, 255, 255);">******test success*********</font><br> </div> <div style="color: rgb(0, 0, 0); font-family: Calibri,Helvetica,sans-serif; font-size: 12pt;"> <span style="display: inline !important; background-color: rgb(255, 255, 255); font-size: 11pt; font-size-adjust: none"><font face="arial"></font><font size="2"></font><font color="#001000"></font>$ gst-launch-1.0 videotestsrc pattern=ball num-buffers=100 ! avenc_bmp ! filesink location=multi_bmp.bin</span><br style="font-family: " font-size: 14.66px"> <span style="display: inline !important; background-color: rgb(255, 255, 255); font-size: 11pt; font-size-adjust: none"></span>*****test fail*********<br style="font-family: " font-size: 14.66px"> <span style="display: inline !important; background-color: rgb(255, 255, 255); font-size: 11pt; font-size-adjust: none">$ gst-launch-1.0 -e filesrc location=multi_bmp.bin ! typefind ! avdec_bmp ! videoconvert ! autovideosink</span></div> <div style="color: rgb(0, 0, 0); font-family: Calibri,Helvetica,sans-serif; font-size: 12pt;"> <br> </div> <div style="color: rgb(0, 0, 0); font-family: Calibri,Helvetica,sans-serif; font-size: 12pt;"> Should I have to implement a customized parser to de-mux the unique frame and deliver it to downstream from a <span style="display: inline !important; background-color: rgb(255, 255, 255); font-family: Calibri,Helvetica,sans-serif; font-size: 12pt; font-size-adjust: none"> still-image</span> bitstream?</div> <div style="color: rgb(0, 0, 0); font-family: Calibri,Helvetica,sans-serif; font-size: 12pt;"> like:</div> <div style="color: rgb(0, 0, 0); font-family: Calibri,Helvetica,sans-serif; font-size: 12pt;"> <span style="display: inline !important; background-color: rgb(255, 255, 255); font-size: 11pt; font-size-adjust: none">$ cat /dev/myusbdev | gst-launch-1.0 fdsrc ! still-image-parse ! decodebin3 ! videoconvert ! fbdevsink</span></div> <div style="color: rgb(0, 0, 0); font-family: Calibri,Helvetica,sans-serif; font-size: 12pt;"> <span style="display: inline !important; background-color: rgb(255, 255, 255); font-size: 11pt; font-size-adjust: none">or can I directly write a C callback function to do the de-mux and delivery the frame to appsrc through g_signal_connect()?</span></div> <div style="color: rgb(0, 0, 0); font-family: Calibri,Helvetica,sans-serif; font-size: 12pt;"> <span style="display: inline !important; background-color: rgb(255, 255, 255); font-size: 11pt; font-size-adjust: none"><br> </span></div> <div style="color: rgb(0, 0, 0); font-family: Calibri,Helvetica,sans-serif; font-size: 12pt;"> <span style="display: inline !important; background-color: rgb(255, 255, 255); font-size: 11pt; font-size-adjust: none">I am new to gstreamer world and would like to find a solution with less efforts to dig into gstreamer hierarchy.</span></div> <div style="color: rgb(0, 0, 0); font-family: Calibri,Helvetica,sans-serif; font-size: 12pt;"> <span style="display: inline !important; background-color: rgb(255, 255, 255); font-size: 11pt; font-size-adjust: none"><br> </span></div> <div style="color: rgb(0, 0, 0); font-family: Calibri,Helvetica,sans-serif; font-size: 12pt;"> <span style="display: inline !important; background-color: rgb(255, 255, 255); font-size: 11pt; font-size-adjust: none">Thanks again for your instructions.</span></div> <div style="color: rgb(0, 0, 0); font-family: Calibri,Helvetica,sans-serif; font-size: 12pt;"> Weidong</div> <div style="color: rgb(0, 0, 0); font-family: Calibri,Helvetica,sans-serif; font-size: 12pt;"> www.nxelec.com</div> <div style="color: rgb(0, 0, 0); font-family: Calibri,Helvetica,sans-serif; font-size: 12pt;"> <span style="display: inline !important; background-color: rgb(255, 255, 255); font-size: 11pt; font-size-adjust: none"><br> </span></div> <div style="color: rgb(0, 0, 0); font-family: Calibri,Helvetica,sans-serif; font-size: 12pt;"> <br> </div> <div id="appendonsend"></div> <hr style="display:inline-block;width:98%" tabindex="-1"> <div id="divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" style="font-size:11pt" color="#000000"><b>发件人:</b> Antonio Ospite <ao2@ao2.it><br> <b>发送时间:</b> 2019年1月8日 0:36<br> <b>收件人:</b> gstreamer-devel@lists.freedesktop.org<br> <b>抄送:</b> Zhou Weidong<br> <b>主题:</b> Re: How to decode a still-image bitstream in MS bitmap format?</font> <div> </div> </div> <div class="BodyFragment"><font size="2"><span style="font-size:11pt;"> <div class="PlainText">On Sat, 5 Jan 2019 05:00:07 +0000<br> Zhou Weidong <weidong.zhou@hotmail.com> wrote:<br> <br> > Hello, All<br> > <br> > I am a software engineer from NXElec and working in a project with<br> > bitstream in MS bitmap format.<br> ><br> > Our target board receives a bitmap bitstream from USB port and we want<br> > to use gstreamer/decodebin3 to decode it. The problem/issue we<br> > currently facing is that decodebin3 hang when the bitstream sent from<br> > the USB Host, and the log messages:<br> [...]<br> <br> I tried to simulate a test without involving USB:<br> <br> $ gst-launch-1.0 videotestsrc pattern=ball num-buffers=100 ! avenc_bmp ! filesink location=multi_bmp.bin<br> <br> And tried to decode multi_bmp.bin:<br> <br> $ gst-launch-1.0 -e filesrc location=multi_bmp.bin ! typefind ! avdec_bmp ! videoconvert ! autovideosink<br> <br> This fails (even for a single frame tho), because avdec_bmp does not get<br> the full frame:<br> <br> ERROR libav :0:: not enough data (4096 < 307254), trying to decode anyway<br> ERROR libav :0:: not enough data (4042 < 307200)<br> <br> Using multifilesrc would work for a single file, but not for multiple<br> BMPs.<br> <br> I used avdec_bmp because using decodebin3 (which picks up gdkpixbufdec)<br> did not work well for me with autovideosink.<br> <br> > To compare with a similar situation, we save an unique still image to<br> > a bitmap file and use gstreamer filesrc to decode it. This time,<br> > decode success. The log messages as below:<br> [...]<br> <br> > I noticed the difference between 2 scenarios is that decodebin3<br> > detects an EOS signal when it read from a bitmap file. And in USB<br> > device mode, there is no EOS signal detecting and this leads<br> > decodebin3 hang...<br> ><br> <br> When loading a single frame you can pass it all at once to the decoder<br> and it will know how to decode it, I think the EOS marks the end of the<br> frame buffer in your second test.<br> <br> When sending multiple frames without a container you need something to<br> tell when one frame ends or, I guess depending on the decoder, to pass<br> single full frames one by one to the decoder.<br> <br> This is the job of a "parser" element in GStreamer.<br> <br> > So the question is how can we use decodebin3 to decode a bitmap<br> > bitstream? Bitmap bitstream here means a bitstream that contents<br> > consequent still images in MS Bitmap format. Currently we send this<br> > bitmap stream from Windows Host, I guess add some tags/delimiters<br> > among images in bitstream will let decodebin3 recognize and decode it<br> > properly. But I do not know how.<br> ><br> <br> A possible solution is to write a bmpparse element to split the<br> bitstream into single frames:<br> <br> $ gst-launch-1.0 -e filesrc location=multi_bmp.bin ! bmpparse ! avdec_bmp ! videoconvert ! autovideosink<br> <br> I hacked up a proof-of-concept with an hardcoded buffer size in pyhton<br> and it seems to do the job.<br> <br> > Thanks in advance if any suggestions/clues come. The current<br> > gstreamer/decodebin3 version we are using is 1.10.4.<br> > <br> <br> Try to use the latest stable version if possible.<br> <br> Ciao,<br> Antonio<br> <br> -- <br> Antonio Ospite<br> <a href="https://ao2.it">https://ao2.it</a><br> <a href="https://twitter.com/ao2it">https://twitter.com/ao2it</a><br> <br> A: Because it messes up the order in which people normally read text.<br> See <a href="http://en.wikipedia.org/wiki/Posting_style">http://en.wikipedia.org/wiki/Posting_style</a><br> Q: Why is top-posting such a bad thing?<br> </div> </span></font></div> </body> </html>