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• C flags which gives priority to quality for decoded images in ffmpeg

  18 janvier 2016, par Tank2005

  I’m trying to decode h.264 streaming with ffmpeg(latest version) on Android NDK.

  I succeeded to get a decoded frame. But, an aquired image is very dirty even if low latency flag is disabled.

  If I want to give priority to quality over decoding speed, which flags should I specify ?

  bool initCodec(bool low_latency)
  
  {
  
      av_register_all();
  
  
  
      codec = avcodec_find_decoder(AV_CODEC_ID_H264);
  
      if(!codec) return false;
  
  
  
      context = avcodec_alloc_context3(codec);
  
      if(!context) return false;
  
  
  
      if(codec->capabilities & CODEC_CAP_TRUNCATED) context->flags |= CODEC_FLAG_TRUNCATED;
  
      if(low_latency == true) context->flags |= CODEC_FLAG_LOW_DELAY;
  
  
  
      frame = av_frame_alloc();
  
  
  
      int res = avcodec_open2(context, codec, NULL);
  
      if (res < 0) {
  
          qDebug() << "Coundn't open codec :" << res;
  
          return false;
  
      }
  
  
  
      av_init_packet(&avpkt);
  
      return true;
  
  }
  
  
  
  void sendBytes(unsigned char *buf, int buflen)
  
  {
  
      avpkt.size = buflen;
  
      avpkt.data = buf;
  
  
  
      int got_frame, len;
  
      while (avpkt.size > 0) {
  
          len = avcodec_decode_video2(context, frame, &got_frame, &avpkt);
  
          if (len < 0) {
  
              qDebug() << "Error while decoding : " << len;
  
              break;
  
          }
  
          if (got_frame) {
  
              onGotFrame(frame);
  
          }
  
          avpkt.size -= len;
  
          avpkt.data += len;
  
      }
  
  }

  

  Ex : I heard that it made a problem while compiling the library. So I write a compile option here(I built it on OpenSUSE Linux).

  #!/bin/bash
  
  NDK=/home/ndk
  
  SYSROOT=$NDK/platforms/android-9/arch-arm/
  
  TOOLCHAIN=$NDK/toolchains/arm-linux-androideabi-4.9/prebuilt/linux-x86_64
  
  function build_one
  
  {
  
  ./configure \
  
  --prefix=$PREFIX \
  
  --enable-shared \
  
  --disable-static \
  
  --disable-avdevice \
  
  --disable-doc \
  
  --disable-symver \
  
  --disable-encoders \
  
  --disable-decoders \
  
  --enable-decoder=h264 \
  
  --enable-decoder=aac \
  
  --disable-protocols \
  
  --disable-demuxers \
  
  --disable-muxers \
  
  --disable-filters \
  
  --disable-network \
  
  --disable-parsers \
  
  --cross-prefix=$TOOLCHAIN/bin/arm-linux-androideabi- \
  
  --target-os=linux \
  
  --arch=arm \
  
  --enable-asm --enable-yasm \
  
  --enable-cross-compile \
  
  --sysroot=$SYSROOT \
  
  --extra-cflags="-Os -marm -march=armv7-a -mfloat-abi=softfp -mfpu=neon" \
  
  --extra-ldflags="-Wl,--fix-cortex-a8" \
  
  $ADDITIONAL_CONFIGURE_FLAG
  
  make clean
  
  make
  
  make install
  
  }
  
  CPU=armv7-a
  
  PREFIX=$(pwd)/android/$CPU
  
  build_on

• 10 Proven Ways Heatmaps Improve Website Conversions

  20 septembre 2021, par Ben Erskine — Analytics Tips, Plugins, Heatmap
  

  Heatmap analytics are critical in improving website conversions. Why ? Because they provide customer-centric insights. 

  In the online market, businesses that are customer-centric are 60% more profitable than businesses that are not.

  Using heatmaps to track factors such as usability, compare A/B landing pages and content engagement across channels optimises online conversions by addressing issues faced by real users. 

  How heatmaps benefit your customers

  Customer experience is one of the most important factors in business success. 

  Website heatmap software like Matomo offers unique insights into customer behaviour that is then used to improve their experience, usability and engagement. 

  Data analysis captures information on how many people complete a sales funnel or bounce from a website. Behavioural analytics like heatmaps can show you why they bounce.

  This benefits your customers (and therefore your bottom line) because it puts the focus on them and their needs.

  10 ways heatmap analytics help increase website conversions

  #1. Improve UX/Usability 

  Heatmap analytics improve usability by identifying where you are losing customers on your website.

  Forrester research indicates that improving user experience can improve conversions by up to 400%, and on average every $1 spent on UX has a return of $100. 

  For example, you may have a CTA button but customers never click it to reach the payment page. 

  Heatmaps show you how customers interact with your website naturally so that you can adjust it according to their needs.

  Using heatmap analytics to improve usability boosts conversions because it improves customer experiences. 88% of online consumers say that they wouldn’t even bother returning to a website after a bad experience. 

  #2. Website design and content structure 

  Another way that heatmaps can improve conversions is to analyse your website design and content structure. 

  You might be wondering how often a specific ad or a banner was displayed and viewed by your visitors on any of your pages and how often a visitor actually interacted with them. These two parts of the analysis are called content impression and content interaction.

  Ideally, your website elements such as banners, listings, buttons and thumbnails will entice customers to click and find out more. 

  Heatmaps and click maps analyse

  1. How many impressions the content has (e.g. a banner), and
  2. What percent of users that see the content click on it 

  For example, you may have a banner with high impressions but low click-through rates. Tracking content interactions optimises your website by showing which elements or CTAs need more visibility. 

  #3. A/B testing

  Heatmaps provide invaluable data on which landing pages are converting the best. Not only that, but session recordings and heatmap data can show you exactly why one is converting better so that you can replicate the results to increase conversions on other landing pages.

  Tracking heatmap updates on different versions of the same sales page will help confirm creative solutions faster than feedback alone. 

  Ultimately this kind of comparison increases your ROI faster because you are not guessing why some customers are converting and others are not. 

  #4. Conversion Funnel

  Using heatmap software in sales funnels lets you visualise user behaviour at each stage of the conversion process. 

  For example, if many customers are dropping off a payment page, heatmaps can indicate whether it is a usability issue such as pop ups, lack of clarity with payment buttons or something web developers haven’t seen from the back end. 

  These analytics improve conversions by reducing friction in sales funnels as much as possible. 

  #5. Content engagement across channels 

  Optimising websites across all channels is now expected for online businesses. 

  Bad mobile optimisation annoys 48% of online shoppers, and if your web page takes longer than 3 seconds to load, 53% of visitors will simply click away. 

  You can use heatmaps to improve engagement by tracking mouse activity, clicks and scrolling. This helps improve conversions by confirming 

  • How invested a user is in the page 
  • How easy it is to navigate your website and content on different devices 
  • What is your most viewed content and what to push more of 
  • How users generally move through your website on different devices 
  • How clear your messaging is (e.g. high click through rate but low engagement could indicate they aren’t finding what they’re looking for once they click on a CTA)

  #6. Above the fold analysis 

  Although a well-used web development term, above the fold is still one of the most important factors in heatmap analysis. 

  Above the fold analysis gives you insight into a customer’s first impression of a page. 

  An example of above-the-fold heatmaps in action could be a page with a video explanation. Say you have a landing page with a video below the fold that explains why someone should buy and has a CTA button underneath. If there are a lot of page visitors but very few people scrolling below the fold, you can see why hardly any visitors are watching the video or engaging with the CTA button. 

  Insights like this would inform further development such as including important video content above the fold or updating header copy to encourage visitors to scroll down the page more often.

  

  #7. Session recording

  Recording features go hand in hand with heatmap visualisations. Recording features like Session Recording shows the flow of each user’s time on your website. 

  For example, a session recording replays all clicks, mouse movements, scrolls, window resizes, form interactions, and page changes (e.g. when a popup appears).

  #8. Scroll heatmap 

  A scroll heatmap shows the percentage of people that have seen a part of the page. 

  For example, the top of a website page will be the “hottest” in a scroll heatmap, and it naturally gets “colder” further down.

  Tracking this shows whether customers are staying on the page, whether they are only seeing information above the fold, and whether sales pages are engaging. 

  It is an effective strategy for improving sales pages because it shows where customers are losing interest and which elements receive the most engagement.

  

  #9. Records clicks 

  With a click heatmap, you can find out what your visitors think is clickable on a webpage.

  This improves conversions in two ways. 

  Firstly, it shows whether customers are clicking where you expect them to. For example, if you create a “buy now” or “free trial” button but nobody ever pushes it, it informs your back end developers that it needs an upgrade. 

  Secondly, it indicates any user experience issues. If there are a lot of clicks on an element that doesn’t link anywhere, it shows that it either needs to be changed or have a link included because customers are trying to engage with it. 

  For even more accurate data, combine click maps with hover maps. This shows where users are paying attention but not clicking through. 

  #10. Records mouse movement/hovering

  Is your website distracting users from the ultimate goal of converting ? Does your website have a logical flow and next step ? Recording mouse movement and attention will help you answer questions like these. 

  Mouse move and hover heatmaps identify where your website visitors engage on the page. Are they naturally drawn to your CTAs ? Is the sidebar taking their attention away from the primary content ? 

  This data increases the likelihood of conversions because it shows where you need to remove distractions or draw their attention in. 

  

  Final thoughts on heatmap analytics 

  Heatmap analytics benefit both you and your customers. By identifying issues that stop them from buying and optimise their engagement, you’ll have happy customers and happy stakeholders. 

  Next, check out these guides on heatmap software and using user behaviour analytics to increase conversions and improve customer experience !

  The Ultimate Guide to Heatmap Software

  Heatmap Video

  Session Recording Video

• FFMpeg Android Stagefright SIGSEGV error (h264 decode)

  19 avril 2013, par Sergey Ochkur

  I need to decode h264 file to YUV on Android 2.3+. As I understand I need to communicate with Stagefright, as it`s the only way now, after closing access with OpenMAX IL implementations. I have used FFmpeg 0.10 (and tried 0.9/0.9.1..) for this issue, compiled it with NDK7 (and also tried NDK6b with the same result) :

    ffmpeg version 0.10 Copyright (c) 2000-2012 the FFmpeg developers
  
    built on Jan 28 2012 14:42:37 with gcc 4.4.3
  
    configuration: --target-os=linux --cross-prefix=arm-linux-androideabi- --arch=arm --cpu=armv7-a --sysroot=/home/grid/Android/Android_NDK/platforms/android-9/arch-arm --disable-avdevice --disable-decoder=h264 --disable-decoder=h264_vdpau --enable-libstagefright-h264 --prefix=build/stagefright/armeabi-v7a --extra-cflags='-Iandroid-source/frameworks/base/include -Iandroid-source/system/core/include -Iandroid-source/frameworks/base/media/libstagefright -Iandroid-source/frameworks/base/include/media/stagefright/openmax -I/home/grid/Android/Android_NDK/sources/cxx-stl/system/include -march=armv7-a -mfloat-abi=softfp -mfpu=neon' --extra-ldflags='-Wl,--fix-cortex-a8 -Landroid-libs -Wl,-rpath-link,android-libs' --extra-cxxflags='-Wno-multichar -fno-exceptions -fno-rtti'
  
    libavutil      51. 34.101 / 51. 34.101
  
    libavcodec     53. 60.100 / 53. 60.100
  
    libavformat    53. 31.100 / 53. 31.100
  
    libavfilter     2. 60.100 /  2. 60.100
  
    libswscale      2.  1.100 /  2.  1.100
  
    libswresample   0.  6.100 /  0.  6.100
  
  Hyper fast Audio and Video encoder
  
  usage: ffmpeg [options] [[infile options] -i infile]... {[outfile options] outfile}...

  Hardware : Beagleboard-Xm + TI Android 2.3 (official)

  So, entering next command give me error with 480p :
  ffmpeg -i /sdcard/Video/480p.mp4

  Stopped (signal) ffmpeg -i /sdcard/Video/480p.mp4

  Full Android "answer" from ADB Logcat :
  http://pastebin.com/76JLgtXX

  Android-developers, does anybody know what this error means and how to deal with it ?
  I tried to make DSP window bigger, but with no luck.
  Commands like "stagefright /sdcard/Video/480p.mp4" works fine.

  P.S. Additionally I found that on some bigger files (720p) Android answers next :

  [libstagefright_h264 @ 0xd479b0] Decode failed : 80000000