Recherche avancée
Médias (1)
-
Video d’abeille en portrait
14 mai 2011, par
Mis à jour : Février 2012
Langue : français
Type : Video
Autres articles (75)
-
Taille des images et des logos définissables
9 février 2011, parDans beaucoup d’endroits du site, logos et images sont redimensionnées pour correspondre aux emplacements définis par les thèmes. L’ensemble des ces tailles pouvant changer d’un thème à un autre peuvent être définies directement dans le thème et éviter ainsi à l’utilisateur de devoir les configurer manuellement après avoir changé l’apparence de son site.
Ces tailles d’images sont également disponibles dans la configuration spécifique de MediaSPIP Core. La taille maximale du logo du site en pixels, on permet (...) -
Supporting all media types
13 avril 2011, parUnlike 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 (...)
-
Pas question de marché, de cloud etc...
10 avril 2011Le vocabulaire utilisé sur ce site essaie d’éviter toute référence à la mode qui fleurit allègrement
sur le web 2.0 et dans les entreprises qui en vivent.
Vous êtes donc invité à bannir l’utilisation des termes "Brand", "Cloud", "Marché" etc...
Notre motivation est avant tout de créer un outil simple, accessible à pour tout le monde, favorisant
le partage de créations sur Internet et permettant aux auteurs de garder une autonomie optimale.
Aucun "contrat Gold ou Premium" n’est donc prévu, aucun (...)
Sur d’autres sites (10319)
-
x264 encoding severe quality loss
1er septembre 2020, par SolskGaerI used this repo to encode a mjpeg stream to a h264 one, but the output is not so good. The stream is a series of screenshot of an iPhone. In the output stream, even the lines between two items in the settings app are gone. How do I improve the output stream quality ?
Here is the code snippet that x264-go use to init an encoder


func NewEncoder(w io.Writer, opts *Options) (e *Encoder, err error) {
 e = &Encoder{}

 e.w = w
 e.pts = 0
 e.opts = opts

 e.csp = x264c.CspI420

 e.nals = make([]*x264c.Nal, 3)
 e.img = NewYCbCr(image.Rect(0, 0, e.opts.Width, e.opts.Height))

 param := x264c.Param{}

 if e.opts.Preset != "" && e.opts.Profile != "" {
 ret := x264c.ParamDefaultPreset(&param, e.opts.Preset, e.opts.Tune)
 if ret < 0 {
 err = fmt.Errorf("x264: invalid preset/tune name")
 return
 }
 } else {
 x264c.ParamDefault(&param)
 }

 param.IWidth = int32(e.opts.Width)
 param.IHeight = int32(e.opts.Height)

 param.ICsp = e.csp
 param.BVfrInput = 0
 param.BRepeatHeaders = 1
 param.BAnnexb = 1

 param.ILogLevel = e.opts.LogLevel

 if e.opts.FrameRate > 0 {
 param.IFpsNum = uint32(e.opts.FrameRate)
 param.IFpsDen = 1

 param.IKeyintMax = int32(e.opts.FrameRate)
 param.BIntraRefresh = 1
 }

 if e.opts.Profile != "" {
 ret := x264c.ParamApplyProfile(&param, e.opts.Profile)
 if ret < 0 {
 err = fmt.Errorf("x264: invalid profile name")
 return
 }
 }

 // Allocate on create instead while encoding
 var picIn x264c.Picture
 ret := x264c.PictureAlloc(&picIn, e.csp, int32(e.opts.Width), int32(e.opts.Height))
 if ret < 0 {
 err = fmt.Errorf("x264: cannot allocate picture")
 return
 }
 e.picIn = picIn
 defer func() {
 // Cleanup if intialization fail
 if err != nil {
 x264c.PictureClean(&picIn)
 }
 }()

 e.e = x264c.EncoderOpen(&param)
 if e.e == nil {
 err = fmt.Errorf("x264: cannot open the encoder")
 return
 }

 ret = x264c.EncoderHeaders(e.e, e.nals, &e.nnals)
 if ret < 0 {
 err = fmt.Errorf("x264: cannot encode headers")
 return
 }

 if ret > 0 {
 b := C.GoBytes(e.nals[0].PPayload, C.int(ret))
 n, er := e.w.Write(b)
 if er != nil {
 err = er
 return
 }

 if int(ret) != n {
 err = fmt.Errorf("x264: error writing headers, size=%d, n=%d", ret, n)
 }
 }

 return
}


and the encoder option is defined as


opts := &x264.Options{
 Width: int(width)/2*2,
 Height: int(height)/2*2,
 FrameRate: 15,
 Tune: "zerolatency",
 Preset: "medium",
 Profile: "baseline",
 LogLevel: x264.LogNone,
 }


And I also used ffmpeg(though the api is pretty old)


package screencast

import (

 /*
 #include 
 #include 
 #include 
 #include 
 #include <libavcodec></libavcodec>avcodec.h>
 #include <libavformat></libavformat>avformat.h>
 #include <libavutil></libavutil>avutil.h>
 #include <libavutil></libavutil>opt.h>
 #include <libavutil></libavutil>channel_layout.h>
 #include <libavutil></libavutil>common.h>
 #include <libavutil></libavutil>imgutils.h>
 #include <libavutil></libavutil>mathematics.h>
 #include <libavutil></libavutil>samplefmt.h>

 typedef struct {
 int w, h;
 int pixfmt;
 char *preset[2];
 char *profile;
 int bitrate;
 int got;
 AVCodec *c;
 AVCodecContext *ctx;
 AVFrame *f;
 AVPacket pkt;
 } h264enc_t;

 static int h264enc_new(h264enc_t *m) {
 m->c = avcodec_find_encoder(AV_CODEC_ID_H264);
 m->ctx = avcodec_alloc_context3(m->c);
 m->ctx->width = m->w;
 m->ctx->height = m->h;
 m->ctx->pix_fmt = m->pixfmt;
 m->ctx->time_base = (AVRational){1,10};
 av_opt_set(m->ctx->priv_data, "preset", "slow", 0);
 av_opt_set(m->ctx->priv_data, "tune", "zerolatency", 0);
 av_opt_set(m->ctx->priv_data, "profile", "baseline", 0);
 av_opt_set(m->ctx->priv_data, "crf", "18.0.", 0);
 m->f = av_frame_alloc();
 m->f->format = m->ctx->pix_fmt;
 m->f->width = m->ctx->width;
 m->f->height = m->ctx->height;
 avcodec_open2(m->ctx, m->c, NULL);
 return av_image_alloc(m->f->data, m->f->linesize, m->ctx->width, m->ctx->height, m->ctx->pix_fmt, 32);
 }

 */
 "C"
 "errors"
 "image"
 "unsafe"
 //"log"
)

type H264Encoder struct {
 m C.h264enc_t
 Header []byte
 Pixfmt image.YCbCrSubsampleRatio
 W, H int
 pts int
}

func NewH264Encoder(w, h int) (m *H264Encoder, err error) {
 m = &H264Encoder{}
 m.m.w = (C.int)(w)
 m.m.h = (C.int)(h)
 m.W = w
 m.H = h
 m.Pixfmt = image.YCbCrSubsampleRatio420
 m.m.pixfmt = C.AV_PIX_FMT_YUV420P
 r := C.h264enc_new(&m.m)
 if int(r) < 0 {
 err = errors.New("open encoder failed")
 return
 }
 return
}

func (m *H264Encoder) Encode(img *image.YCbCr) (data []byte, err error) {
 var f *C.AVFrame
 if img == nil {
 f = nil
 } else {
 if img.SubsampleRatio != m.Pixfmt {
 err = errors.New("image pixfmt not match")
 return
 }
 if img.Rect.Dx() != m.W || img.Rect.Dy() != m.H {
 err = errors.New("image size not match")
 return
 }
 f = m.m.f
 f.data[0] = (*C.uint8_t)(unsafe.Pointer(&img.Y[0]))
 f.data[1] = (*C.uint8_t)(unsafe.Pointer(&img.Cb[0]))
 f.data[2] = (*C.uint8_t)(unsafe.Pointer(&img.Cr[0]))
 f.linesize[0] = (C.int)(img.YStride)
 f.linesize[1] = (C.int)(img.CStride)
 f.linesize[2] = (C.int)(img.CStride)
 }

 C.av_init_packet(&m.m.pkt)
 m.m.pkt.data = nil
 m.m.pkt.size = 0
 f.pts = (C.longlong)(m.pts)
 m.pts++
 r := C.avcodec_encode_video2(m.m.ctx, &m.m.pkt, f, &m.m.got)
 defer C.av_packet_unref(&m.m.pkt)
 if int(r) < 0 {
 err = errors.New("encode failed")
 return
 }
 if m.m.got == 0 {
 err = errors.New("no picture")
 return
 }
 if m.m.pkt.size == 0 {
 err = errors.New("packet size == 0")
 return
 }

 data = make([]byte, m.m.pkt.size)
 C.memcpy(
 unsafe.Pointer(&data[0]),
 unsafe.Pointer(m.m.pkt.data),
 (C.size_t)(m.m.pkt.size),
 )
 return data, nil
}


but got the same output. However, when I use the ffmpeg binary, the result was pretty good, so I guess I set wrong parameters, but I don't know which.
Any suggestion would be appreciated. If you have better way to achieve this, I'll appreciate it.


For your information : I must do this using golang.




-
x264 encoding severe quality loss
1er septembre 2020, par SolskGaerI used this repo to encode a mjpeg stream to a h264 one, but the output is not so good. The stream is a series of screenshot of an iPhone. In the output stream, even the lines between two items in the settings app are gone. How do I improve the output stream quality ?
Here is the code snippet that x264-go use to init an encoder


func NewEncoder(w io.Writer, opts *Options) (e *Encoder, err error) {
 e = &Encoder{}

 e.w = w
 e.pts = 0
 e.opts = opts

 e.csp = x264c.CspI420

 e.nals = make([]*x264c.Nal, 3)
 e.img = NewYCbCr(image.Rect(0, 0, e.opts.Width, e.opts.Height))

 param := x264c.Param{}

 if e.opts.Preset != "" && e.opts.Profile != "" {
 ret := x264c.ParamDefaultPreset(&param, e.opts.Preset, e.opts.Tune)
 if ret < 0 {
 err = fmt.Errorf("x264: invalid preset/tune name")
 return
 }
 } else {
 x264c.ParamDefault(&param)
 }

 param.IWidth = int32(e.opts.Width)
 param.IHeight = int32(e.opts.Height)

 param.ICsp = e.csp
 param.BVfrInput = 0
 param.BRepeatHeaders = 1
 param.BAnnexb = 1

 param.ILogLevel = e.opts.LogLevel

 if e.opts.FrameRate > 0 {
 param.IFpsNum = uint32(e.opts.FrameRate)
 param.IFpsDen = 1

 param.IKeyintMax = int32(e.opts.FrameRate)
 param.BIntraRefresh = 1
 }

 if e.opts.Profile != "" {
 ret := x264c.ParamApplyProfile(&param, e.opts.Profile)
 if ret < 0 {
 err = fmt.Errorf("x264: invalid profile name")
 return
 }
 }

 // Allocate on create instead while encoding
 var picIn x264c.Picture
 ret := x264c.PictureAlloc(&picIn, e.csp, int32(e.opts.Width), int32(e.opts.Height))
 if ret < 0 {
 err = fmt.Errorf("x264: cannot allocate picture")
 return
 }
 e.picIn = picIn
 defer func() {
 // Cleanup if intialization fail
 if err != nil {
 x264c.PictureClean(&picIn)
 }
 }()

 e.e = x264c.EncoderOpen(&param)
 if e.e == nil {
 err = fmt.Errorf("x264: cannot open the encoder")
 return
 }

 ret = x264c.EncoderHeaders(e.e, e.nals, &e.nnals)
 if ret < 0 {
 err = fmt.Errorf("x264: cannot encode headers")
 return
 }

 if ret > 0 {
 b := C.GoBytes(e.nals[0].PPayload, C.int(ret))
 n, er := e.w.Write(b)
 if er != nil {
 err = er
 return
 }

 if int(ret) != n {
 err = fmt.Errorf("x264: error writing headers, size=%d, n=%d", ret, n)
 }
 }

 return
}


and the encoder option is defined as


opts := &x264.Options{
 Width: int(width)/2*2,
 Height: int(height)/2*2,
 FrameRate: 15,
 Tune: "zerolatency",
 Preset: "medium",
 Profile: "baseline",
 LogLevel: x264.LogNone,
 }


And I also used ffmpeg(though the api is pretty old)


package screencast

import (

 /*
 #include 
 #include 
 #include 
 #include 
 #include <libavcodec></libavcodec>avcodec.h>
 #include <libavformat></libavformat>avformat.h>
 #include <libavutil></libavutil>avutil.h>
 #include <libavutil></libavutil>opt.h>
 #include <libavutil></libavutil>channel_layout.h>
 #include <libavutil></libavutil>common.h>
 #include <libavutil></libavutil>imgutils.h>
 #include <libavutil></libavutil>mathematics.h>
 #include <libavutil></libavutil>samplefmt.h>

 typedef struct {
 int w, h;
 int pixfmt;
 char *preset[2];
 char *profile;
 int bitrate;
 int got;
 AVCodec *c;
 AVCodecContext *ctx;
 AVFrame *f;
 AVPacket pkt;
 } h264enc_t;

 static int h264enc_new(h264enc_t *m) {
 m->c = avcodec_find_encoder(AV_CODEC_ID_H264);
 m->ctx = avcodec_alloc_context3(m->c);
 m->ctx->width = m->w;
 m->ctx->height = m->h;
 m->ctx->pix_fmt = m->pixfmt;
 m->ctx->time_base = (AVRational){1,10};
 av_opt_set(m->ctx->priv_data, "preset", "slow", 0);
 av_opt_set(m->ctx->priv_data, "tune", "zerolatency", 0);
 av_opt_set(m->ctx->priv_data, "profile", "baseline", 0);
 av_opt_set(m->ctx->priv_data, "crf", "18.0.", 0);
 m->f = av_frame_alloc();
 m->f->format = m->ctx->pix_fmt;
 m->f->width = m->ctx->width;
 m->f->height = m->ctx->height;
 avcodec_open2(m->ctx, m->c, NULL);
 return av_image_alloc(m->f->data, m->f->linesize, m->ctx->width, m->ctx->height, m->ctx->pix_fmt, 32);
 }

 */
 "C"
 "errors"
 "image"
 "unsafe"
 //"log"
)

type H264Encoder struct {
 m C.h264enc_t
 Header []byte
 Pixfmt image.YCbCrSubsampleRatio
 W, H int
 pts int
}

func NewH264Encoder(w, h int) (m *H264Encoder, err error) {
 m = &H264Encoder{}
 m.m.w = (C.int)(w)
 m.m.h = (C.int)(h)
 m.W = w
 m.H = h
 m.Pixfmt = image.YCbCrSubsampleRatio420
 m.m.pixfmt = C.AV_PIX_FMT_YUV420P
 r := C.h264enc_new(&m.m)
 if int(r) < 0 {
 err = errors.New("open encoder failed")
 return
 }
 return
}

func (m *H264Encoder) Encode(img *image.YCbCr) (data []byte, err error) {
 var f *C.AVFrame
 if img == nil {
 f = nil
 } else {
 if img.SubsampleRatio != m.Pixfmt {
 err = errors.New("image pixfmt not match")
 return
 }
 if img.Rect.Dx() != m.W || img.Rect.Dy() != m.H {
 err = errors.New("image size not match")
 return
 }
 f = m.m.f
 f.data[0] = (*C.uint8_t)(unsafe.Pointer(&img.Y[0]))
 f.data[1] = (*C.uint8_t)(unsafe.Pointer(&img.Cb[0]))
 f.data[2] = (*C.uint8_t)(unsafe.Pointer(&img.Cr[0]))
 f.linesize[0] = (C.int)(img.YStride)
 f.linesize[1] = (C.int)(img.CStride)
 f.linesize[2] = (C.int)(img.CStride)
 }

 C.av_init_packet(&m.m.pkt)
 m.m.pkt.data = nil
 m.m.pkt.size = 0
 f.pts = (C.longlong)(m.pts)
 m.pts++
 r := C.avcodec_encode_video2(m.m.ctx, &m.m.pkt, f, &m.m.got)
 defer C.av_packet_unref(&m.m.pkt)
 if int(r) < 0 {
 err = errors.New("encode failed")
 return
 }
 if m.m.got == 0 {
 err = errors.New("no picture")
 return
 }
 if m.m.pkt.size == 0 {
 err = errors.New("packet size == 0")
 return
 }

 data = make([]byte, m.m.pkt.size)
 C.memcpy(
 unsafe.Pointer(&data[0]),
 unsafe.Pointer(m.m.pkt.data),
 (C.size_t)(m.m.pkt.size),
 )
 return data, nil
}


but got the same output. However, when I use the ffmpeg binary, the result was pretty good, so I guess I set wrong parameters, but I don't know which.
Any suggestion would be appreciated. If you have better way to achieve this, I'll appreciate it.


For your information : I must do this using golang.




-
video not playing on iOS safari
21 octobre 2020, par Dean Van GreunenThis video plays perfectly on Chrome Desktop and Android Chrome, on the latest releases.


However it won't work on an iPad and an iPhone.




also here is the file info.




Syndiquer tout le site
