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• Replacing the standard Android H264 software encoder with an ffmpeg based one

  10 août 2012, par rubenvb

  In Android ICS and later, a new OpenMax IL API version is in use, making old binary blobs useless/unused. This leads to older devices that otherwise run ICS just fine and dandy to have broken video playback (YouTube HQ and IMBD, for example) because Androids fallback software decoder sucks when compared to what ffmpeg can do on the same device (I tested MXPlayer+arm6vfp ffmpeg and a 720p movie played back great).

  I am trying to dig through the Android source code to see where and what exactly I could add/replace code to allow the ffmpeg library's awesomeness to be used. The problem is I don't know exactly what code is being used in for example the YouTube app to decode video, or how that's decided.

  So I have two options as far as I can tell :

  1. Figure out the current software decoder being used, and try to wrap its external interface around ffmpeg, effectively replacing the slow software decoder currently used. The end result would be a single .so I could push to the device.

  2. Figure out how to trick Android into thinking an OMX library based on ffmpeg (I have built one succesfully for Android : limoa) and add this somewhere to the list of considered libraries (or better : replace the unusable hardware codec).

  As an extension, I'd like to also make camcorder video encoding work through this, so a true integrated solution would be very much wanted. The question is : how, and where, and what ? Searching the Android source tree gives numerous counts of "H264" and related stuff in many different places. I need the lowest and simplest possible, so I can simply wrap the hypothetical decode(buffer) function call to use ffmpeg (libavcodec).

• Need help finding a way to use avconv or ffmpeg to convert any video to an exact size and shape

  29 octobre 2013, par mikecole79

  This is for work. We have a system that supports streaming video, but we support multiple players. I have multiple systems that I COULD use for this. Currently, I've been using the media server that we use to stream the video, which has ffmpeg on it (running Red Hat 4). On that system, I've used :

   ffmpeg -i INPUT_FILE.mp4 -c:v libx264 -crf 23 -maxrate 3000k -bufsize 30000k -c:a aac -strict experimental -b:a 192k -filter:v "scale=iw*min($width/iw\,$height/ih):ih*min($width/iw\,$height/ih), pad=$width:$height:($width-iw*min($width/iw\,$height/ih))/2:($height-ih*min($width/iw\,$height/ih))/2" -f OUTPUT_FILE.mp4

  And I thought that it worked well. On one file I used to test, it seemed to display properly on both player types. On a different file, it did not appear properly. The input files are also in varying formats (mostly mp4, with a few m4g files) and different aspect ratios.

  We also have many desktop/laptop machines that are running Ubuntu 13.04 (comes with avconv) that I'd like to be able to use to format video as well. If I can get at least one of these systems to properly format video, that would be great, but ideally I'd like to figure out how to do this with both avconv AND ffmpeg so I can use any system.

  The problem that we're trying to solve is that one player is an Android DMP device, which will play a video of varying sizes properly by adding black bars at the sides or top/bottom as needed to keep the video sized properly. The other player is a Samsung Smart TV, which is SO Smart that it can reformat videos to fit the screen. Which sucks horribly, because if they're not sized to exactly the right format, it will stretch them one direction or another to make them be sized right. The resulting video show's people that appear to be 8 feet tall weighing 130 pounds, or 4 feet tall and 3 feet wide.

  Obviously, this isn't what we desire, but I lack the knowledge of avconv/ffmpeg to do anything to fix it. I need an expert, and I am not he. Nor is anyone I currently work with an expert on this subject. Anyone that is, I'd appreciate your help more than I can express via a web interface.

  Thanks !

• truehd : break out part of rematrix_channels into platform-specific callback.

  20 mars 2014, par Ben Avison

  truehd : break out part of rematrix_channels into platform-specific callback.
  Verified with profiling that this doesn’t have a measurable effect upon
  
  overall performance.
  Signed-off-by : Michael Niedermayer <michaelni@gmx.at>
  

  • [DH] libavcodec/mlpdec.c
  • [DH] libavcodec/mlpdsp.c
  • [DH] libavcodec/mlpdsp.h