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• Loading and unloading C jni library based on when it's needed

  30 septembre 2014, par Alin

  I finally managed to compile ffmpeg for android and I’ve been able to use it in my app.

  Here is the scenario of my app :

  • I show the user a gridview with thumbnails of images and videos
  • the user can click on a cell and it is taken to image/video details where he can see the full image or play the video
  • the user can apply an image over an video and this is when ffmpeg is used

  So basically, the user might never actually use the watermarking option or he can do it very rare because the amount of available videos is way smaller than images.

  I am loading the ffmpeg library, first time it is needed by running :

  static {
  
       System.loadLibrary("ffmpeglib");
  
  }

  Now here are my questions :

  1. loading the library like this, uses app’s memory and resources ?
  2. can I unload the library, or better said, is it needed to unload it ? I have not found any java code like System.unloadLibrary to take care of unloading
  3. Since the library might be used rarely, wouldn’t a load => do encoding => unload be a better approach ? Or maybe having it loaded would allow easy reuse since no loading is necessary.
  4. If I use an IntentService to load the library and make the encoding, when the service completes the job, does the library gets unloaded ?

• VP8 Codec SDK "Aylesbury" Release

  28 octobre 2010, par noreply@blogger.com (John Luther)

  Today we’re making available "Aylesbury," our first named release of libvpx, the VP8 codec SDK. VP8 is the video codec used in WebM. Note that the VP8 specification has not changed, only the SDK.

  What’s an Aylesbury ? It’s a breed of duck. We like ducks, so we plan to use duck-related names for each major libvpx release, in alphabetical order. Our goal is to have one named release of libvpx per calendar quarter, each with a theme.

  You can download the Aylesbury libvpx release from our Downloads page or check it out of our Git repository and build it yourself. In the coming days Aylesbury will be integrated into all of the WebM project components (DirectShow filters, QuickTime plugins, etc.). We encourage anyone using our components to upgrade to the Aylesbury releases.

  For Aylesbury the theme was faster decoder, better encoder. We used our May 19, 2010 launch release of libvpx as the benchmark. We’re very happy with the results (see graphs below) :
  

  • 20-40% (average 28%) improvement in libvpx decoder speed
  • Over 7% overall PSNR improvement (6.3% SSIM) in VP8 "best" quality encoding mode, and up to 60% improvement on very noisy, still or slow moving source video.

  

  
  

  

  
  

  

  
  

  The main improvements to the decoder are :
  

  • Single-core assembly "hot spot" optimizations, including improved vp8_sixtap_predict() and SSE2 loopfilter functions
  • Threading improvements for more efficient use of multiple processor cores
  • Improved memory handling and reduced footprint
  • Combining IDCT and reconstruction steps
  • SSSE3 usage in functions where appropriate

  On the encoder front, we concentrated on clips in the 30-45 dB range and saw the biggest gains in higher-quality source clips (greater that 38 dB), low to medium-motion clips, and clips with noisy source material. Many code contributions made this possible, but a few of the highlights were :
  

  • Adaptive width and strength alternate reference frame noise suppression filter with optional motion compensation.
  • Transform improvements (improved accuracy and reduction in round trip error)
  • Trellis-based quantized coefficient optimization
  • Two-pass rate control and quantizer changes
  • Rate distortion changes
  • Zero bin and rounding changes
  • Work on MB-level quality control and bit allocation

  We’re targeting Q1 2011 for the next named libvpx release, which we’re calling Bali. The theme for that release will be faster encoder. We are constantly working on improvements to video quality in the encoder, so after Aylesbury we won’t tie that work to specific named releases.

  WebM at Streaming Media West

  Members of the WebM project will discuss Aylesbury during a session at the Streaming Media West conference on November 3rd (session C203 : WebM Open Video Project Update). For more information, visit www.streamingmedia.com/west.

  John Luther is Product Manager of the WebM Project.

  

• HLS Encoding Resulting in "No Supported Source Was Found"

  18 février 2023, par Paulamonopoly

  I'm currently facing the most bizare problems I've come across, so I'm hoping someone can explain why this is happening. I'm currently converting my Movie and Show libary to HLS for buffering and bandwidth reasons etc.

  


  My file structure for these movies and shows are as follows :

  


  /Movies/[TMDB ID]/[TMDB ID].mp4

  


  /Shows/[TMDB ID/[Season Number]/[Episode Number]/[Episode Number].mp4

  


  I have converted my entire movie collection successfully using the below command.

  


  find /* -type f -name "*.mp4" -exec realpath {} \; -exec ffmpeg -i {} -codec: copy -start_number 0 -hls_time 10 -hls_list_size 0 -f hls -hls_segment_filename '{}-P%03d' {}.m3u8 \;


  


  This is taking my named mp4 files and converting them to the originalname.m3u8 with chunks following the naming scheme of originalname-PXXX where P indicates the part number. I know there's no file extensions attached with the chunks but it's not needed.

  


  You can view this result here : Example

  


  This result also works if loaded into HLS Player : HLS Player

  


  So there is evidently nothing wrong with the converting of my videos or even the result of the videos.

  


  Now, if I convert a TV Show using the exact same command, it does indeed convert them, it does use a slightly different file structure as with seasons and episodes etc which can be seen above, but now it results in the error : "No Supported Source Was Found" in the console and repeatedly tries to play Part 000 without success.

  


  This can be seen here : Example

  


  And the errors if loaded into HLS Player : HLS Player

  


  I have tried changing numerous things to try and resolve this error as well as checking things, the things I have checked are the media condition itself maybe it's a corrupted file ?

  


  The original Mp4 file can be played here without any problems, so we know the Mp4 file originally is perfectly fine. I have also tried adding a file extension to the chunks such as .ts and .mp4 etc etc with also no success.

  


  I have even thought maybe it's the directories so I have moved a show into the movies directory with no success, I have also moved a movie into the show directory which resulted in a working HLS Stream so it's nothing to do with the directories.

  


  I have tried exending the file name length thinking it's possibly the naming scheme with 1.m3u8 not been long enough of a file name by using placeholder text such as 03051.m3u8 as well as the chunk naming scheme 03051-PXXX possibly not been long enough.

  


  I have noticed though that using this command :

  


  ffmpeg -allowed_extensions ALL -i {} -c copy -bsf:a aac_adtstoasc {}.mkv \;


  


  Does recombine my HLS video correctly with the same file size etc, however I have noticed that the video itself is corrupt and doesn't play. So this makes be believe the issue lies within the converting of the initial Mp4 file into m3u8.