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Valkaama DVD Label
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Mis à jour : Février 2013
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Mis à jour : Mai 2011
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Autres articles (98)
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List of compatible distributions
26 avril 2011, parThe table below is the list of Linux distributions compatible with the automated installation script of MediaSPIP. Distribution nameVersion nameVersion number Debian Squeeze 6.x.x Debian Weezy 7.x.x Debian Jessie 8.x.x Ubuntu The Precise Pangolin 12.04 LTS Ubuntu The Trusty Tahr 14.04
If you want to help us improve this list, you can provide us access to a machine whose distribution is not mentioned above or send the necessary fixes to add (...) -
(Dés)Activation de fonctionnalités (plugins)
18 février 2011, parPour gérer l’ajout et la suppression de fonctionnalités supplémentaires (ou plugins), MediaSPIP utilise à partir de la version 0.2 SVP.
SVP permet l’activation facile de plugins depuis l’espace de configuration de MediaSPIP.
Pour y accéder, il suffit de se rendre dans l’espace de configuration puis de se rendre sur la page "Gestion des plugins".
MediaSPIP est fourni par défaut avec l’ensemble des plugins dits "compatibles", ils ont été testés et intégrés afin de fonctionner parfaitement avec chaque (...) -
Problèmes fréquents
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Sur d’autres sites (9583)
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Availability of WebM (VP8) Video Hardware IP Designs
10 janvier 2011, par noreply@blogger.com (John Luther)Hello from the frigid city of Oulu, in the far north of Finland. Our WebM hardware development team, formerly part of On2 Technologies, is now up-to-speed and working hard on a number of video efforts for WebM.
- VP8 (the video codec used in WebM) hardware decoder IP is available from Google for semiconductor companies who want to support high-quality WebM playback in their chipsets.
- The Oulu team will release the first VP8 video hardware encoder IP in the first quarter of 2011. We have the IP running in an FPGA environment, and rigorous testing is underway. Once all features have been tested and implemented, the encoder will be launched as well.
WebM video hardware IPs are implemented and delivered as RTL (VHDL/Verilog) source code, which is a register-level hardware description language for creating digital circuit designs. The code is based on the Hantro brand video IP from On2, which has been successfully deployed by numerous chipset companies around the world. Our designs support VP8 up to 1080p resolution and can run 30 or 60fps, depending on the foundry process and hardware clock frequency.
The WebM/VP8 hardware decoder implementation has already been licensed to over twenty partners and is proven in silicon. We expect the first commercial chips to integrate our VP8 decoder IP to be available in the first quarter of 2011. For example, Chinese semiconductor maker Rockchip last week demonstrated full WebM hardware playback on their new RK29xx series processor at CES in Las Vegas (video below).
Note : To view the video in WebM format, ensure that you’ve enrolled in the YouTube HTML5 trial and are using a WebM-compatible browser. You can also view the video on YouTube.Hardware implementations of the VP8 encoder also bring exciting possibilities for WebM in portable devices. Not only can hardware-accelerated devices play high-quality WebM content, but hardware encoding also enables high-resolution, real-time video communications apps on the same devices. For example, when VP8 video encoding is fully off-loaded to a hardware accelerator, you can run 720p or even 1080p video conferencing at full framerate on a portable device with minimal battery use.
The WebM hardware video IP team will be focusing on further developing the VP8 hardware designs while also helping our semiconductor partners to implement WebM video compression in their chipsets. If you have any questions, please visit our Hardware page.
Happy New Year to the WebM community !
Jani Huoponen, Product Manager
Aki Kuusela, Engineering Manager -
Can't initialize "h264_mediacodec" for hw accelerated decoding, FFMPEG, Android
27 mars 2024, par Ramil GalinI am trying to create hw accelerated decoding on Android through JNI and following this example but, unfortunately,
avcodec_get_hw_configreturns nullptr.

I have also tried using
avcodec_find_decoder_by_name("h264_mediacodec"), also returns nullptr.

I built ffmpeg (version 4.4) using this script with the flags :


--enable-jni \
--enable-mediacodec \
--enable-decoder=h264_mediacodec \
--enable-hwaccel=h264_mediacodec \


When configuring build I saw in logs
WARNING: Option --enable-hwaccel=h264_mediacodec did not match anything, which is actually strange. FFMPEG 4.4 should support hw accelerated decoding using mediacodec.

Edit : (providing minimal reproducible example)


In the JNI method I init input context of decoder and init decoder :


void Decoder::initInputContext(
 const std::string& source,
 AVDictionary* options
 ) { // open input, and allocate format context
 if (
 avformat_open_input(
 &m_inputFormatContext,
 source.c_str(),
 NULL,
 options ? &options : nullptr
 ) < 0
 ) {
 throw FFmpegException(
 fmt::format("Decoder: Could not open source {}", source)
 );
 }
 
 // retrieve stream information
 if (avformat_find_stream_info(m_inputFormatContext, NULL) < 0) {
 throw FFmpegException(
 "Decoder: Could not find stream information"
 );
 }

 // get audio and video streams
 for (size_t i = 0; i < m_inputFormatContext->nb_streams; i++) {
 AVStream* inStream = m_inputFormatContext->streams[i];
 AVCodecParameters* inCodecpar = inStream->codecpar;
 if (
 inCodecpar->codec_type != AVMEDIA_TYPE_AUDIO &&
 inCodecpar->codec_type != AVMEDIA_TYPE_VIDEO
 ) {
 continue;
 }

 if (inCodecpar->codec_type == AVMEDIA_TYPE_VIDEO) {
 m_videoStreamIdx = i;
 m_videoStream = inStream;

 m_codecParams.videoCodecId = m_videoStream->codecpar->codec_id;
 m_codecParams.fps = static_cast<int>(av_q2d(m_videoStream->r_frame_rate) + 0.5);
 m_codecParams.clockrate = m_videoStream->time_base.den;

 spdlog::debug(
 "Decoder: fps: {}, clockrate: {}",
 m_codecParams.fps,
 m_codecParams.clockrate
 )
 ;
 }

 if (inCodecpar->codec_type == AVMEDIA_TYPE_AUDIO) {
 m_audioStreamIdx = i;
 m_audioStream = inStream;

 m_codecParams.audioCodecId = m_audioStream->codecpar->codec_id;
 m_codecParams.audioSamplerate = m_audioStream->codecpar->sample_rate;
 m_codecParams.audioChannels = m_audioStream->codecpar->channels;
 m_codecParams.audioProfile = m_audioStream->codecpar->profile;

 spdlog::debug(
 "Decoder: audio samplerate: {}, audio channels: {}, x: {}",
 m_codecParams.audioSamplerate,
 m_codecParams.audioChannels,
 m_audioStream->codecpar->channels
 )
 ;
 }
 }
 }

 void Decoder::initDecoder() {
 AVCodecParameters* videoStreamCodecParams = m_videoStream->codecpar;

 m_swsContext = sws_getContext(
 videoStreamCodecParams->width, videoStreamCodecParams->height, m_pixFormat,
 videoStreamCodecParams->width, videoStreamCodecParams->height, m_targetPixFormat,
 SWS_BICUBIC, nullptr, nullptr, nullptr);

 // find best video stream info and decoder
 int ret = av_find_best_stream(m_inputFormatContext, AVMEDIA_TYPE_VIDEO, -1, -1, &m_decoder, 0);
 if (ret < 0) {
 throw FFmpegException(
 "Decoder: Cannot find a video stream in the input file"
 );
 }

 if (!m_decoder) {
 throw FFmpegException(
 "Decoder: Can't find decoder"
 );
 }

 // search for supported HW decoder configuration
 for (size_t i = 0;; i++) {
 const AVCodecHWConfig* config = avcodec_get_hw_config(m_decoder, i);
 if (!config) {
 spdlog::error(
 "Decoder {} does not support device type {}. "
 "Will use SW decoder...",
 m_decoder->name,
 av_hwdevice_get_type_name(m_deviceType)
 );
 break;
 }

 if (
 config->methods & AV_CODEC_HW_CONFIG_METHOD_HW_DEVICE_CTX &&
 config->device_type == m_deviceType
 ) {
 // set up pixel format for HW decoder
 g_hwPixFmt = config->pix_fmt;
 m_hwDecoderSupported = true;
 break;
 }
 }
 }
</int>

And I have
AVHWDeviceType m_deviceType{AV_HWDEVICE_TYPE_MEDIACODEC};

avcodec_get_hw_configreturns nullptr.

Any help is appreciated.


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Encode video of powerpoint presentation for HTML5 playback
17 avril 2013, par user2291446We have a number of powerpoint presentations that have been converted to 16:9
aspect ratio and then converted into mp4 "master videos" with an "apple TV" 720p
profile. These powerpoint presentations are voice annotated. So in essence, we
show a slide and then let the annotation sound play for a while, then go to the
next slide, and so on. The resulting mp4 master video is somewhere around 900MB
on average.Here is an example of the master video
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'input.mp4' : Metadata : major_brand : isom minor_version : 512 compatible_brands : isomiso2avc1mp41 creation_time : 1970-01-01 00:00:00 encoder : Lavf52.104.0 Duration : 02:00:57.65, start : 0.000000, bitrate : 970 kb/s Stream #0:0(und) : Video : h264 (Main) (avc1 / 0x31637661), yuv420p, 1280x720 [SAR 1:1 DAR 16:9], 836 kb/s, 29.97 fps, 29.97 tbr, 30k tbn, 59.94 tbc Metadata : creation_time : 1970-01-01 00:00:00 handler_name : VideoHandler Stream #0:1(und) : Audio : aac (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 127 kb/s Metadata : creation_time : 1970-01-01 00:00:00 handler_name : SoundHandlerWe are trying to get these presentations to play on the web on as many
devices/browsers as possible including some that don't do HTML5 (IE7/IE8). We
have narrowed down our player of choice which is mediaElement and have extracted
some "cue points" from the powerpoint presentation that mark where the slides
are changing. We have also captured thumbnails for those cuepoints such that we
now have a nice list of thumbnails for each slide and an associated cuepoint in
the video where the particular slide begins.Here comes the problem...due to the large size of the master video it is not
practical for us to use the master video with our mediaElement player. We do
need to transcode the master video to mp4 and ogv in order to get decent
device/browser coverage.We do not seem to be able to find a suitable transcoding strategy to reduce the
size of the video. We have played with numerous ffmpeg settings and were able to
reduce the size but when we do so we compromise the ability to jump to specific
cue points.It works well for browsers that do HTML5 video natively (Chrome and Firefox) but
not for the flash fallback of mediaElement (IE7/IE8) which uses the mp4 file and
seemingly is very tied to the number and frequency of key frames in the video in
order to allow for clean seeking and skipping using the cue points.Seeing that we are talking about a video that has only slides (practically 90
static images per presentation) and some sound we imagine it must be possible to
transcode as such that the keyframes fall at the cue points or near the
cuepoints, and that the size of the video could be drastically reduced while
still allowing for smooth seeking and skipping.
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