Recherche avancée
Médias (1)
-
MediaSPIP Simple : futur thème graphique par défaut ?
26 septembre 2013, par
Mis à jour : Octobre 2013
Langue : français
Type : Video
Autres articles (96)
-
MediaSPIP 0.1 Beta version
25 avril 2011, parMediaSPIP 0.1 beta is the first version of MediaSPIP proclaimed as "usable".
The zip file provided here only contains the sources of MediaSPIP in its standalone version.
To get a working installation, you must manually install all-software dependencies on the server.
If you want to use this archive for an installation in "farm mode", you will also need to proceed to other manual (...) -
HTML5 audio and video support
13 avril 2011, parMediaSPIP 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 (...) -
ANNEXE : Les plugins utilisés spécifiquement pour la ferme
5 mars 2010, parLe site central/maître de la ferme a besoin d’utiliser plusieurs plugins supplémentaires vis à vis des canaux pour son bon fonctionnement. le plugin Gestion de la mutualisation ; le plugin inscription3 pour gérer les inscriptions et les demandes de création d’instance de mutualisation dès l’inscription des utilisateurs ; le plugin verifier qui fournit une API de vérification des champs (utilisé par inscription3) ; le plugin champs extras v2 nécessité par inscription3 (...)
Sur d’autres sites (9646)
-
The ffmpeg webm_dash_manifest demuxer fails with webvtt subtitles
30 janvier 2020, par HyldreanI am trying to create a DASH manifest using ffmpeg and I encounter some difficulties with the subtitles. I get the error
[webm_dash_manifest @ 0x55e19db48180] EBML header parsing failed
[webm_dash_manifest @ 0x55e19db48180] Failed to read file headers
subtitles.vtt: Operation not permittedThe subtitles are encoded in the plain text webvtt format. I first assume that the EBML header are missing because the subtitles were not contained in a webm container. I then tried to create a webm file containing only the subtitles. It appears impossible.
I think the problem comes from the webm_dash_manifest demuxer. It seeks metadata in a file with no metadata. However neither Google nor Stack Overflow give me an answer.
The command I used :
ffmpeg \
-f webm_dash_manifest -i video.webm \
-f webm_dash_manifest -i audio.webm \
-f webm_dash_manifest -i subtitles.vtt \
-map 0 -map 1 -map 2 \
-c copy \
-f webm_dash_manifest \
-adaptation_sets "id=0,streams=0 id=1,streams=1 id=2,stream=2" \
minimal.mpdand the ffmpeg output :
ffmpeg version 3.2.14-1~deb9u1 Copyright (c) 2000-2019 the FFmpeg developers
built with gcc 6.3.0 (Debian 6.3.0-18+deb9u1) 20170516
configuration: --prefix=/usr --extra-version='1~deb9u1' --toolchain=hardened --libdir=/usr/lib/x86_64-linux-gnu --incdir=/usr/include/x86_64-linux-gnu --enable-gpl --disable-stripping --enable-avresample --enable-avisynth --enable-gnutls --enable-ladspa --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libcdio --enable-libebur128 --enable-libflite --enable-libfontconfig --enable-libfreetype --enable-libfribidi --enable-libgme --enable-libgsm --enable-libmp3lame --enable-libopenjpeg --enable-libopenmpt --enable-libopus --enable-libpulse --enable-librubberband --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libssh --enable-libtheora --enable-libtwolame --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx265 --enable-libxvid --enable-libzmq --enable-libzvbi --enable-omx --enable-openal --enable-opengl --enable-sdl2 --enable-libdc1394 --enable-libiec61883 --enable-chromaprint --enable-frei0r --enable-libopencv --enable-libx264 --enable-shared
libavutil 55. 34.101 / 55. 34.101
libavcodec 57. 64.101 / 57. 64.101
libavformat 57. 56.101 / 57. 56.101
libavdevice 57. 1.100 / 57. 1.100
libavfilter 6. 65.100 / 6. 65.100
libavresample 3. 1. 0 / 3. 1. 0
libswscale 4. 2.100 / 4. 2.100
libswresample 2. 3.100 / 2. 3.100
libpostproc 54. 1.100 / 54. 1.100
[webm_dash_manifest @ 0x55e19db17160] Could not find codec parameters for stream 0 (Video: vp9, none, 1280x534): unspecified pixel format
Consider increasing the value for the 'analyzeduration' and 'probesize' options
Input #0, webm_dash_manifest, from 'video.webm':
Metadata:
title : Cloud Atlas
ENCODER : Lavf58.35.104
Duration: 00:05:00.01, bitrate: 998 kb/s
Chapter #0:0: start 0.000000, end 300.000000
Metadata:
title : Chapter 01
Stream #0:0(eng): Video: vp9, none, 1280x534, SAR 1:1 DAR 640:267, 23.98 fps, 23.98 tbr, 1k tbn, 1k tbc (default) (forced)
Metadata:
title : Video @ 6.9 Mbps [frame B:188517 Avg QP:20.66]
ENCODER : Lavc58.66.100 libvpx-vp9
DURATION : 00:05:00.008000000
webm_dash_manifest_duration: 300008
webm_dash_manifest_initialization_range: 900
webm_dash_manifest_file_name: video.webm
webm_dash_manifest_track_number: 1
webm_dash_manifest_cues_start: 37455991
webm_dash_manifest_cues_end: 37457486
webm_dash_manifest_bandwidth: 1420427
webm_dash_manifest_cluster_keyframe: 1
webm_dash_manifest_cue_timestamps: 298715
Input #1, webm_dash_manifest, from 'audio.webm':
Metadata:
title : Cloud Atlas
ENCODER : Lavf58.35.104
Duration: 00:05:00.01, bitrate: 126 kb/s
Chapter #1:0: start 0.000000, end 300.000000
Metadata:
title : Chapter 01
Stream #1:0(eng): Audio: opus, 48000 Hz, stereo, fltp (default)
Metadata:
title : Audio Eng DTS 5.1 channels 24 bits @ 1509 Kbps cbr
ENCODER : Lavc58.66.100 libopus
DURATION : 00:05:00.007000000
webm_dash_manifest_duration: 300007
webm_dash_manifest_initialization_range: 838
webm_dash_manifest_file_name: audio.webm
webm_dash_manifest_track_number: 1
webm_dash_manifest_cues_start: 4744091
webm_dash_manifest_cues_end: 4745279
webm_dash_manifest_bandwidth: 137531
webm_dash_manifest_cluster_keyframe: 1
webm_dash_manifest_cue_timestamps: 295000
[webm_dash_manifest @ 0x55e19db48180] EBML header parsing failed
[webm_dash_manifest @ 0x55e19db48180] Failed to read file headers
subtitles.vtt: Operation not permittedI noticed that
ffmpeg -f webm_dash_manifest -i subtitles.vttsuffices to reproduce the error.I have also tried without the
-f webm_dash_manifestflag, with no success :ffmpeg \
-f webm_dash_manifest -i video.webm \
-f webm_dash_manifest -i audio.webm \
-i subtitles.vtt \
-map 0 -map 1 -map 2 \
-c copy \
-f webm_dash_manifest \
-adaptation_sets "id=0,streams=0 id=1,streams=1 id=2,stream=2" minimal.mpdOutput :
ffmpeg version 3.2.14-1~deb9u1 Copyright (c) 2000-2019 the FFmpeg developers
built with gcc 6.3.0 (Debian 6.3.0-18+deb9u1) 20170516
configuration: --prefix=/usr --extra-version='1~deb9u1' --toolchain=hardened --libdir=/usr/lib/x86_64-linux-gnu --incdir=/usr/include/x86_64-linux-gnu --enable-gpl --disable-stripping --enable-avresample --enable-avisynth --enable-gnutls --enable-ladspa --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libcdio --enable-libebur128 --enable-libflite --enable-libfontconfig --enable-libfreetype --enable-libfribidi --enable-libgme --enable-libgsm --enable-libmp3lame --enable-libopenjpeg --enable-libopenmpt --enable-libopus --enable-libpulse --enable-librubberband --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libssh --enable-libtheora --enable-libtwolame --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx265 --enable-libxvid --enable-libzmq --enable-libzvbi --enable-omx --enable-openal --enable-opengl --enable-sdl2 --enable-libdc1394 --enable-libiec61883 --enable-chromaprint --enable-frei0r --enable-libopencv --enable-libx264 --enable-shared
libavutil 55. 34.101 / 55. 34.101
libavcodec 57. 64.101 / 57. 64.101
libavformat 57. 56.101 / 57. 56.101
libavdevice 57. 1.100 / 57. 1.100
libavfilter 6. 65.100 / 6. 65.100
libavresample 3. 1. 0 / 3. 1. 0
libswscale 4. 2.100 / 4. 2.100
libswresample 2. 3.100 / 2. 3.100
libpostproc 54. 1.100 / 54. 1.100
[webm_dash_manifest @ 0x557f55dd1160] Could not find codec parameters for stream 0 (Video: vp9, none, 1280x534): unspecified pixel format
Consider increasing the value for the 'analyzeduration' and 'probesize' options
Input #0, webm_dash_manifest, from 'video.webm':
Metadata:
title : Cloud Atlas
ENCODER : Lavf58.35.104
Duration: 00:05:00.01, bitrate: 998 kb/s
Chapter #0:0: start 0.000000, end 300.000000
Metadata:
title : Chapter 01
Stream #0:0(eng): Video: vp9, none, 1280x534, SAR 1:1 DAR 640:267, 23.98 fps, 23.98 tbr, 1k tbn, 1k tbc (default) (forced)
Metadata:
title : Video @ 6.9 Mbps [frame B:188517 Avg QP:20.66]
ENCODER : Lavc58.66.100 libvpx-vp9
DURATION : 00:05:00.008000000
webm_dash_manifest_duration: 300008
webm_dash_manifest_initialization_range: 900
webm_dash_manifest_file_name: video.webm
webm_dash_manifest_track_number: 1
webm_dash_manifest_cues_start: 37455991
webm_dash_manifest_cues_end: 37457486
webm_dash_manifest_bandwidth: 1420427
webm_dash_manifest_cluster_keyframe: 1
webm_dash_manifest_cue_timestamps: 298715
Input #1, webm_dash_manifest, from 'audio.webm':
Metadata:
title : Cloud Atlas
ENCODER : Lavf58.35.104
Duration: 00:05:00.01, bitrate: 126 kb/s
Chapter #1:0: start 0.000000, end 300.000000
Metadata:
title : Chapter 01
Stream #1:0(eng): Audio: opus, 48000 Hz, stereo, fltp (default)
Metadata:
title : Audio Eng DTS 5.1 channels 24 bits @ 1509 Kbps cbr
ENCODER : Lavc58.66.100 libopus
DURATION : 00:05:00.007000000
webm_dash_manifest_duration: 300007
webm_dash_manifest_initialization_range: 838
webm_dash_manifest_file_name: audio.webm
webm_dash_manifest_track_number: 1
webm_dash_manifest_cues_start: 4744091
webm_dash_manifest_cues_end: 4745279
webm_dash_manifest_bandwidth: 137531
webm_dash_manifest_cluster_keyframe: 1
webm_dash_manifest_cue_timestamps: 295000
Input #2, webvtt, from 'subtitles.vtt':
Duration: N/A, bitrate: N/A
Stream #2:0: Subtitle: webvtt
Could not write header for output file #0 (incorrect codec parameters ?): Operation not permittedStream mapping:
Stream #0:0 -> #0:0 (copy)
Stream #1:0 -> #0:1 (copy)
Stream #2:0 -> #0:2 (copy)
Last message repeated 1 timesNote :
[webm_dash_manifest @ 0x557f55dd1160] Could not find codec parameters for stream 0 (Video: vp9, none, 1280x534): unspecified pixel formatis harmless according to this post.The subtitles have been extracted with ffmpeg :
ffmpeg -i "Cloud Atlas.mkv" -map 0:6 -t 00:05:00 -c:s webvtt -dash 1 subtitles.vttThank you for reading my long post, I have no idea what to do next.
EDIT : The WebM Project website says : ’Initial WebM release does not support subtitles’. Has someone heard of a new release ? Or a convenient way to create DASH manifest with subtitles ?
-
Call to avformat_find_stream_info prevents decoding of simple PNG image ?
10 avril 2014, par kloffyI am running into a problem decoding a simple PNG image with libav. The
decode_okflag after the call toavcodec_decode_video2is set to0, even though the packet contains the entire image. Through some experimentation, I have managed to pinpoint the issue and it seems related to callingavformat_find_stream_info. If the call is removed, the example runs successfully. However, I would like to use the same code for other media, and callingavformat_find_stream_infois recommended in the documentation.The following minimal example illustrates the behavior (unfortunately still a bit lengthy) :
#include <iostream>
extern "C"
{
#include <libavformat></libavformat>avformat.h>
#include <libavcodec></libavcodec>avcodec.h>
}
// Nothing to see here, it's just a helper function
AVCodecContext* open(AVMediaType mediaType, AVFormatContext* formatContext)
{
auto ret = 0;
if ((ret = av_find_best_stream(formatContext, mediaType, -1, -1, nullptr, 0)) < 0)
{
std::cerr << "Failed to find video stream." << std::endl;
return nullptr;
}
auto codecContext = formatContext->streams[ret]->codec;
auto codec = avcodec_find_decoder(codecContext->codec_id);
if (!codec)
{
std::cerr << "Failed to find codec." << std::endl;
return nullptr;
}
if ((ret = avcodec_open2(codecContext, codec, nullptr)) != 0)
{
std::cerr << "Failed to open codec context." << std::endl;
return nullptr;
}
return codecContext;
}
// All the interesting bits are here
int main(int argc, char* argv[])
{
auto path = "/path/to/test.png"; // Replace with valid path to PNG
auto ret = 0;
av_log_set_level(AV_LOG_DEBUG);
av_register_all();
avcodec_register_all();
auto formatContext = avformat_alloc_context();
if ((ret = avformat_open_input(&formatContext, path, NULL, NULL)) != 0)
{
std::cerr << "Failed to open input." << std::endl;
return -1;
}
av_dump_format(formatContext, 0, path, 0);
//*/ Info is successfully found, but interferes with decoding
if((ret = avformat_find_stream_info(formatContext, nullptr)) < 0)
{
std::cerr << "Failed to find stream info." << std::endl;
return -1;
}
av_dump_format(formatContext, 0, path, 0);
//*/
auto codecContext = open(AVMEDIA_TYPE_VIDEO, formatContext);
AVPacket packet;
av_init_packet(&packet);
if ((ret = av_read_frame(formatContext, &packet)) < 0)
{
std::cerr << "Failed to read frame." << std::endl;
return -1;
}
auto frame = av_frame_alloc();
auto decode_ok = 0;
if ((ret = avcodec_decode_video2(codecContext, frame, &decode_ok, &packet)) < 0 || !decode_ok)
{
std::cerr << "Failed to decode frame." << std::endl;
return -1;
}
av_frame_free(&frame);
av_free_packet(&packet);
avcodec_close(codecContext);
avformat_close_input(&formatContext);
av_free(formatContext);
return 0;
}
</iostream>The format dump before
avformat_find_stream_infoprints :Input #0, image2, from '/path/to/test.png' : Duration : N/A, bitrate : N/A Stream #0:0, 0, 1/25 : Video : png, 25 tbnThe format dump after
avformat_find_stream_infoprints :Input #0, image2, from '/path/to/test.png' : Duration : 00:00:00.04, start : 0.000000, bitrate : N/A Stream #0:0, 1, 1/25 : Video : png, rgba, 512x512 [SAR 3780:3780 DAR 1:1], 1/25, 25 tbr, 25 tbn, 25 tbcSo it looks like the search yields potentially useful information. Can anybody shed some light on this problem ? Other image formats seem to work fine. I assume that this is a simple user error rather than a bug.
Edit : Debug logging was already enabled, but the PNG decoder does not produce a lot of output. I have also tried setting a custom logging callback.
Here is what I get without the call to
avformat_find_stream_info, when decoding succeeds :Statistics : 52125 bytes read, 0 seeks
And here is what I get with the call to
avformat_find_stream_info, when decoding fails :Statistics : 52125 bytes read, 0 seeks
detected 8 logical cores
The image is 52125 bytes, so the whole file is read. I am not sure what the logical cores are referring to.
-
avformat/mov : fix seeking with HEVC open GOP files
18 février 2022, par Clément Bœschavformat/mov : fix seeking with HEVC open GOP files
This was tested with medias recorded from an iPhone XR and an iPhone 13.
Here is how a typical stream looks like in coding order :
┌────────┬─────┬─────┬──────────┐
│ sample | PTS | DTS | keyframe |
├────────┼─────┼─────┼──────────┤
┊ ┊ ┊ ┊ ┊
│ 53 │ 560 │ 510 │ No │
│ 54 │ 540 │ 520 │ No │
│ 55 │ 530 │ 530 │ No │
│ 56 │ 550 │ 540 │ No │
│ 57 │ 600 │ 550 │ Yes │
│ * 58 │ 580 │ 560 │ No │
│ * 59 │ 570 │ 570 │ No │
│ * 60 │ 590 │ 580 │ No │
│ 61 │ 640 │ 590 │ No │
│ 62 │ 620 │ 600 │ No │
┊ ┊ ┊ ┊ ┊In composition/display order :
┌────────┬─────┬─────┬──────────┐
│ sample | PTS | DTS | keyframe |
├────────┼─────┼─────┼──────────┤
┊ ┊ ┊ ┊ ┊
│ 55 │ 530 │ 530 │ No │
│ 54 │ 540 │ 520 │ No │
│ 56 │ 550 │ 540 │ No │
│ 53 │ 560 │ 510 │ No │
│ * 59 │ 570 │ 570 │ No │
│ * 58 │ 580 │ 560 │ No │
│ * 60 │ 590 │ 580 │ No │
│ 57 │ 600 │ 550 │ Yes │
│ 63 │ 610 │ 610 │ No │
│ 62 │ 620 │ 600 │ No │
┊ ┊ ┊ ┊ ┊Sample/frame 58, 59 and 60 are B-frames which actually depends on the
key frame (57). Here the key frame is not an IDR but a "CRA" (Clean
Random Access).Initially, I thought I could rely on the sdtp box (independent and
disposable samples), but unfortunately :sdtp[54] is_leading:0 sample_depends_on:1 sample_is_depended_on:0 sample_has_redundancy:0
sdtp[55] is_leading:0 sample_depends_on:1 sample_is_depended_on:2 sample_has_redundancy:0
sdtp[56] is_leading:0 sample_depends_on:1 sample_is_depended_on:2 sample_has_redundancy:0
sdtp[57] is_leading:0 sample_depends_on:2 sample_is_depended_on:0 sample_has_redundancy:0
sdtp[58] is_leading:0 sample_depends_on:1 sample_is_depended_on:0 sample_has_redundancy:0
sdtp[59] is_leading:0 sample_depends_on:1 sample_is_depended_on:2 sample_has_redundancy:0
sdtp[60] is_leading:0 sample_depends_on:1 sample_is_depended_on:2 sample_has_redundancy:0
sdtp[61] is_leading:0 sample_depends_on:1 sample_is_depended_on:0 sample_has_redundancy:0
sdtp[62] is_leading:0 sample_depends_on:1 sample_is_depended_on:0 sample_has_redundancy:0The information that might have been useful here would have been
is_leading, but all the samples are set to 0 so this was unusable.Instead, we need to rely on sgpd/sbgp tables. In my case the video track
contained 3 sgpd tables with the following grouping types : tscl, sync
and tsas. In the sync table we have the following 2 entries (only) :sgpd.sync[1] : sync nal_unit_type:0x14
sgpd.sync[2] : sync nal_unit_type:0x15(The count starts at 1 because 0 carries the undefined semantic, we'll
see that later in the reference table).The NAL unit types presented here correspond to :
libavcodec/hevc.h : HEVC_NAL_IDR_N_LP = 20,
libavcodec/hevc.h : HEVC_NAL_CRA_NUT = 21,In parallel, the sbgp sync table contains the following :
┌────┬───────┬─────┐
│ id │ count │ gdi │
├────┼───────┼─────┤
│ 0 │ 1 │ 1 │
│ 1 │ 56 │ 0 │
│ 2 │ 1 │ 2 │
│ 3 │ 59 │ 0 │
│ 4 │ 1 │ 2 │
│ 5 │ 59 │ 0 │
│ 6 │ 1 │ 2 │
│ 7 │ 59 │ 0 │
│ 8 │ 1 │ 2 │
│ 9 │ 59 │ 0 │
│ 10 │ 1 │ 2 │
│ 11 │ 11 │ 0 │
└────┴───────┴─────┘The gdi column (group description index) directly refers to the index in
the sgpd.sync table. This means the first frame is an IDR, then we have
batches of undefined frames interlaced with CRA frames. No IDR ever
appears again (tried on a 30+ seconds sample).With that information, we can build an heuristic using the presentation
order.A few things needed to be introduced in this commit :
1. min_sample_duration is extracted from the stts : we need the minimal
step between sample in order to PTS-step backward to a valid point
2. In order to avoid a loop over the ctts table systematically during a
seek, we build an expanded list of sample offsets which will be used
to translate from DTS to PTS
3. An open_key_samples index to keep track of all the non-IDR key
frames ; for now it only supports HEVC CRA frames. We should probably
add BLA frames as well, but I don't have any sample so I prefered to
leave that for laterIt is entirely possible I missed something obvious in my approach, but I
couldn't come up with a better solution. Also, as mentioned in the diff,
we could optimize is_open_key_sample(), but the linear scaling overhead
should be fine for now since it only happens in seek events.Fixing this issue prevents sending broken packets to the decoder. With
FFmpeg hevc decoder the frames are skipped, with VideoToolbox the frames
are glitching.
Syndiquer tout le site
