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Video d’abeille en portrait
14 mai 2011, par
Mis à jour : Février 2012
Langue : français
Type : Video
Autres articles (42)
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MediaSPIP : Modification des droits de création d’objets et de publication définitive
11 novembre 2010, parPar défaut, MediaSPIP permet de créer 5 types d’objets.
Toujours par défaut les droits de création et de publication définitive de ces objets sont réservés aux administrateurs, mais ils sont bien entendu configurables par les webmestres.
Ces droits sont ainsi bloqués pour plusieurs raisons : parce que le fait d’autoriser à publier doit être la volonté du webmestre pas de l’ensemble de la plateforme et donc ne pas être un choix par défaut ; parce qu’avoir un compte peut servir à autre choses également, (...) -
Personnaliser les catégories
21 juin 2013, parFormulaire de création d’une catégorie
Pour ceux qui connaissent bien SPIP, une catégorie peut être assimilée à une rubrique.
Dans le cas d’un document de type catégorie, les champs proposés par défaut sont : Texte
On peut modifier ce formulaire dans la partie :
Administration > Configuration des masques de formulaire.
Dans le cas d’un document de type média, les champs non affichés par défaut sont : Descriptif rapide
Par ailleurs, c’est dans cette partie configuration qu’on peut indiquer le (...) -
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.
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Sur d’autres sites (8482)
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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.




-
ffmpeg fix video orientation
22 juillet 2020, par PiTheNumberA video can contain a meta info about the camera orientation. For example iPhone and other phones set this flag if you turn the device. Problem is while some player read this info and rotate the video accordingly, other players do not.



To fix this the video has to be rotated and the meta info needs to be set correctly.



Does ffmpeg provide a fix for this or do I have to go the hard way (Read rotation, rotate, set meta data)


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