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• What is the best solution to convert old videos to newer more optimised formats ? [on hold]

  9 septembre 2019, par Jack

  Not too sure if this is the wrong place - please move it as I couldn’t find a more suitable network

  I have loads of media (Movies, TV Shows) as well as home videos (old VHS stuff ripped using some awful VHS to digital kit)

  Most of the movies/TV shows are in H264 (MP4/MKV containers) format, however some older ones are in AVI and WMV - I’d like to convert these into either H264 or a newer format (HEVC ?) To save some disk space and also because WMVs and AVIs are getting harder to deal with nowadays. I’m concerned about losing quality and am wondering what would be the best compromise in terms of converting these to HEVC/MPEG4’s encoder quality settings as compared to the data savings.

  The media collection of TV shows/movies, I don’t mind too much about losing some quality but the home videos/VHS tapes I have in old file formats, the storage factor for these is less important but I was wondering what I’d need to do to convert old AVI’s/MPEG2’s to MPEG4/HEVC - mainly if it is possible to convert one of these old video files to a newer format, without loss of quality, I thought the newer video encoding’s had lossless and lossy compression, but I could be completely wrong and don’t know much about video codecs.

  I was more curious on the best solution to do this as, Googling it gives me loads of commercial software and I’d rather have something which I can use command line/programmatically against my entire libraries. I also couldn’t find anything on these commercial sites about the technicals of re-encoding video so, was wondering if anyone had any experience with any command line applications/have an understanding of the video codecs.

• Nginx with rtmp-module stalls between streams

  14 janvier 2015, par churchmf

  I’m experiencing some troubles using NGINX with rtmp-module as a media server. I wish to present a continuous video as a live stream (with up to 60 second latency). However, due to some hardware constraints, I am unable to stream directly from the device. Instead, I can save out X amount of seconds from the device’s buffer as an MP4. My solution has been to save X seconds of video from the device then stream that X seconds, rise and repeat. This has been working mostly well, except for stalls ( 20 seconds) in the stream between calls.

  I have searched far and wide for a solution to this however most of the people experiencing this problem have the collection of videos before starting the stream and can simply concatenate them.

  My running theory is that when a stream finishes, it does an unpublish event in NGINX followed by a timeout period. This prevents the NGINX server from receiving the next publish until the timeout period has expired. I have tried adjusting nginx.config values related to timeouts, respawns, restarts, and publish, but to no avail.

  Pseudocode :
  while true
   > capture X seconds of video to "output.mp4" (this takes less than 300ms)
   > stream the MP4 with FFMPEG (takes X seconds using -re)

  FFMPEG call :
  ffmpeg -re -i "output.mp4" -vcodec libx264 -preset veryfast -maxrate 2000k -bufsize 4000k -g 60 -acodec libmp3lame -b:a 128k -ac 2 -ar 44100 -f flv rtmp :/MYSERVER/live/output

  I am using JWPlayer client side to watch the video stream, however I experience similar issues using VLC.

  I have been trying to figure this out for a few days and I would appreciate any insight an expert to video streaming and NGINX can give. Thank you !

• ANSI Code Coverage Followup

  9 mars 2012, par Multimedia Mike — Programming

  The people behind sixteencolors.net noticed my code coverage project concerning the ANSI video decoder and asked what they could do to help. I had already downloaded 350 / 4000 of their artpacks but didn’t want to download the remainder if I could avoid it. They offered to run my tool against their local collection of files.

  Aside : They have all of the artpacks archived at Github.

  The full corpus of nearly 4000 artpacks contains over 146,000 files. Versus my sampling of 350 artpacks and 13,000 files that covered all but 45 lines of the ansi.c source file, the full corpus has files to exercise… 6 more of those lines. Whee. This means that there are files which exercise the reverse and concealed attributes, all 3 “erase in line” modes, and one more error path (which probably wasn’t a valid file anyway).

  Missing features mostly cluster around different video modes, including : 320×200 (25 rows), 640×200 (25 rows), 640×350 (43 rows), and 640×480 (60 rows) ; on the plus side, nothing tripped the “unsupported screen mode” case. There are no files that switch modes during playback.

  I guess statistical sampling theory holds out here– a small set of randomly chosen files would do a fine job covering code. But this experiment is about finding the statistical outliers.