Recherche avancée

Sur d’autres sites (12023)

• Decoding RIMM streaming file format

  10 septembre 2011, par Thomas

  I want to decode the video (visual) frames within a Blackberry RIMM file. So far I have a parser, and some corresponding container documentation from RIM. 

  The video codec is H264 and is explicitly set on the device using one of the video.encodings properties. However, FFMPEG is not able to decode the frames and this is driving me nuts.

  Edit 1 : The issues seems to be lack of SPS and PPS in the frames, and artificially inserting them have proven unsuccessful so far (all grey image). Blackberry 9700 sends

  0x00 0x00 0x ?? 0x ?? 0xType

  where Type is according to table 7-1 in the H264 spec (I and P frames). We believe the 0x ?? 0x ?? represent the size of the frame, however the size does not always correspond to the size found by the parser (the parser seems to be working correctly).

  I have a windows decoder codec from blackberry, called mc_demux_mp2_ds.ax, and can play some MPEG-4 files captured the same way, but it is a binary for windows. And the H264 files will not play either way. I am aware of previous attempts. The capture url for javax.microedition.media.Manager is

  encoding=video-3gpp_width=176_height=144_video_codec=H264_audio_codec=AAC

  and I am writing to an output stream. Some example files here.

  Edit 2 :Turns out that about 3-4 of the 12-15 available video capture modes are flat out failing and refusing to output data, even in the simplest of test applications. So any working solution should implement MPEG-4, H264 and H263 in both AMR and AAC, in so getting fallback alternatives when one sound codec and/or resolution fails. Reboots, hangs and what not litters the Blackberry video implementation and vary from firmware to firmware ; total suckage.

• Connection randomly closes wihtout data while running a FFMPEG PHP script

  23 octobre 2022, par Victor Marinov

  I'm building a simple back-end solution for a client that allows them to upload any video in mo4 or mov format of up to about 500MB in size to a PHP back-end, which then takes the material, downsizes and compresses the it using the PHP library FFMPEG available here https://github.com/PHP-FFMpeg/PHP-FFMpeg.

  


  While the video is being processed the connection to the front-end stays open, awaiting the compression result.

  


  This may normally take up to 3-5 minutes depending on the size and duration of the video.

  


  Overall it functions as intended, but with some videos I get random resets of the connection while the video is being processed.

  


  I've added numerous error_log() lines in my script which show that the script continues running even after the connection is reset and the actual processing and compression of the video completes correctly and the file is saved in the DB and in storage.

  


  Below is a small excerpt from the code in question :

  


                          //THEN COMPRESS VIDEO THUMBNAIL
                        $format = new FFMpeg\Format\Video\X264();
                        $format->setKiloBitrate(3200);
                        error_log("BEFORE COMPRESS! ", 0);

                        //PREVENT ANY ECHO's
                        ob_start();
                        error_log("DURING COMPRESS... ", 0);
                        $video->save($format, $export_path);
                        error_log("JUST AFTER... ", 0);
                        $compress_output = ob_get_clean();

                        $resp['video_compression_result'] = 'success';
                        error_log("COMPRESS SUCCESS! ", 0);


  


  I would just like to know if any of you would have an idea why the connection might be reset on some files and not on others ? I've even tried wrapping the the $video->save() function in an output buffer to prevent any possible output which might trigger an premature output.

  


  I have increased the PHP settings for max_memory to 2G and upload_max_filze and post_max size to 500M.

  


  max_execution_time and max_input_time are both set to 1200 sec. The random reset usually comes at 1.7 or 5.4 minutes into the request and seem to depend on the file selected.

  


  I've successfully processed smaller files from the same source without issues. The only variable here appears to be the duration and size of the video. What is most puzzling to me is that the remaining code continues to run fine even after the connection is reset.

  


  If you have any clues, please let me know as this is driving me crazy for a second day in a row now and spoiling an otherwise perfectly functional solution for the client !

  


• FFMPEG SCREEN RECORDING : How to get H265 (libx265) recording using ffmpeg with xorg ?

  19 novembre 2020, par Ryan

  I really would appreciate all the help I can get here.

  


  I'm trying to use the libx265 codec for recording an xorg dummy screen. The command that currently works for H264 (libx264 codec) is :

  


  


  ffmpeg -y -v info -f x11grab -draw_mouse 0 -r 30 -s 1280x720
-thread_queue_size 4096 -i :0.0+0,0 -f alsa -acodec aac -strict -2 -ar 44100 -b:a 128k -af aresample=async=1 -c:v libx264 -preset fast
-profile:v main -level 3.1 -pix_fmt yuv420p -r 30 -crf 21 -g 60 -tune zerolatency -f mp4 capture.mp4

  


  


  In trying to get H265 instead, I first changed the codec to libx265 like below :

  


  


  ffmpeg -y -v info -f x11grab -draw_mouse 0 -r 30 -s 1280x720
-thread_queue_size 4096 -i :0.0+0,0 -f alsa -acodec aac -strict -2 -ar 44100 -b:a 128k -af aresample=async=1 -c:v libx265 -preset fast
-profile:v main -level 3.1 -pix_fmt yuv420p -r 30 -crf 21 -g 60 -tune zerolatency -f mp4 capture.mp4

  


  


  But that didn't do it. Although it didn't error, it was producing a file that was playing at twice the recorded speed (i.e. twice the speed of the clip that was recorded).

  


  Then I tried using -x265-params to specify the parameters like this :

  


  


  ffmpeg -y -v info -f x11grab -draw_mouse 0 -r 30 -s 1280x720
-thread_queue_size 4096 -i :0.0+0,0 -f alsa -acodec aac -strict -2 -ar 44100 -b:a 128k -af aresample=async=1 -c:v libx264 -preset fast
-x265-params profile=main:level=3.1:crf=21 -pix_fmt yuv420p -r 30 -g 60 -tune zerolatency -f mp4 capture.mp4

  


  


  And this gave me an error with the following message :

  


  "output file #0 does not contain any stream ffmpeg"

  


  I've tried all sorts of combinations, searched extensively online (for both how to set 265 parameters and on the output file error), but I'm not making a headway. I'm really new to all this. Can anyone please help (with the most simple terms and directions) ?