Recherche avancée

Médias (0)

Mot : - Tags -/médias

Aucun média correspondant à vos critères n’est disponible sur le site.

Autres articles (40)

  • Use, discuss, criticize

    13 avril 2011, par

    Talk to people directly involved in MediaSPIP’s development, or to people around you who could use MediaSPIP to share, enhance or develop their creative projects.
    The bigger the community, the more MediaSPIP’s potential will be explored and the faster the software will evolve.
    A discussion list is available for all exchanges between users.

  • Supporting all media types

    13 avril 2011, par

    Unlike most software and media-sharing platforms, MediaSPIP aims to manage as many different media types as possible. The following are just a few examples from an ever-expanding list of supported formats : images : png, gif, jpg, bmp and more audio : MP3, Ogg, Wav and more video : AVI, MP4, OGV, mpg, mov, wmv and more text, code and other data : OpenOffice, Microsoft Office (Word, PowerPoint, Excel), web (html, CSS), LaTeX, Google Earth and (...)

  • HTML5 audio and video support

    13 avril 2011, par

    MediaSPIP uses HTML5 video and audio tags to play multimedia files, taking advantage of the latest W3C innovations supported by modern browsers.
    The MediaSPIP player used has been created specifically for MediaSPIP and can be easily adapted to fit in with a specific theme.
    For older browsers the Flowplayer flash fallback is used.
    MediaSPIP allows for media playback on major mobile platforms with the above (...)

Sur d’autres sites (4586)

  • How to reverse a video using ffmpeg in android ?

    8 janvier 2019, par Kalpesh Kumawat

    I wanna reverse a video which loaded from gallery and Camera. video converts into image frames and frames convert into reverse video using ffmpeg commands.

  • How to reverse a video using ffmpeg in android ?

    28 décembre 2016, par Kalpesh Kumawat

    I wanna reverse a video which loaded from gallery and Camera. video converts into image frames and frames convert into reverse video using ffmpeg commands.

  • ffmpeg hwo to choose the best bit rate for HLS streaming ?

    7 février 2023, par Josef Kranz

    I'm building a video streaming white label product, but I've run into the following scenario where I'm not sure what might be the optimal way to get the best video quality in return. At the moment I'm using crf based encoding, which is from a streaming based point of view a very bad idea. From a quality point of view, it will definitely give me the best quality and also the best efficiency. Why is crf based encoding bad for streaming ? First you have a non-fixed file size, meaning your bit rate might vary between 20 kbps and 20 Mbit/s depending on the codec and picture motion of the current frames ...
When you have such heavily varying stream according to the bit rate, automatic quality selection at the player might not function correctly, and the player automatically switches from 1080p to 480p for no reason (using VideoJS here).

    


    To fix this issue, it's fine if I set minrate, maxrate with ffmpeg but this will also come at the cost that some frames might look pixelated, which I absolutely do not want.

    


    Currently, my encoding command looks something like this :

    


    /usr/bin/ffmpeg -i "/tmp/VODProcessing/Tester 2160p UHD-HDR.mp4" -map 0:0 -c:v libsvtav1 -crf 19 -vf zscale=width=3840:height=2160 -svtav1-params "profile=0:enable-force-key-frames=1:superres-mode=1:enable-tf=0:tune=0:enable-overlays=1:scd=1:scm=2:enable-mfmv=1:enable-cdef=1:enable-dlf=1:fast-decode=1:color-primaries=9:transfer-characteristics=16:matrix-coefficients=9:input-depth=10:mastering-display=G(0.265,0.69)B(0.15,0.06)R(0.68,0.32)WP(0.3127,0.329)L(4000.0,0.005):content-light=368,226:enable-hdr=1:color-range=1" -pix_fmt yuv420p10le -color_trc smpte2084 -color_primaries bt2020 -colorspace bt2020nc -chroma_sample_location:v topleft -color_range:v pc -max_muxing_queue_size 1024 -preset 7 -bf 0 -force_key_frames "expr:gte(t,n_forced*4.004)" -keyint_min 48 -sc_threshold 0 -use_timeline 1 -use_template 1 -map_metadata -1 -map_chapters -1 -f hls -seg_duration 4.004 -hls_time 4.004 -streaming 1 -hls_list_size 0 -hls_segment_filename "/tmp/VODProcessing/output/Tester 2160p UHD-HDR/v-av01-2160p-av01.0.12M.10_PQ/f-%04d.m4s"  -hls_fmp4_init_filename "init-v-av01-2160p-av01.0.12M.10_PQ.m4s"  -hls_segment_type fmp4 -hls_playlist_type vod -movflags frag_keyframe+frag_every_frame+write_colr+prefer_icc+skip_trailer+faststart -hls_flags independent_segments -strict experimental "/tmp/VODProcessing/output/Tester 2160p UHD-HDR/v-av01-2160p-av01.0.12M.10_PQ/master.m3u8"


    


    Which will form a stream made out of independent m4s segments. As you can see, I'm using libsvtav1 in crf mode to output the result in AV1.

    


    Now my question is, how can I have the same nice quality output as with the crf mode while having a static/fixed bit rate ? Will 2 pass encoding solve this problem by distributing the pixels or data rate differently ?

    


    Thanks in advance

    


Navigation