Recherche avancée
Médias (1)
-
The Slip - Artworks
26 septembre 2011, par
Mis à jour : Septembre 2011
Langue : English
Type : Texte
Autres articles (63)
-
Les autorisations surchargées par les plugins
27 avril 2010, parMediaspip core
autoriser_auteur_modifier() afin que les visiteurs soient capables de modifier leurs informations sur la page d’auteurs -
Publier sur MédiaSpip
13 juin 2013Puis-je poster des contenus à partir d’une tablette Ipad ?
Oui, si votre Médiaspip installé est à la version 0.2 ou supérieure. Contacter au besoin l’administrateur de votre MédiaSpip pour le savoir -
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 (...)
Sur d’autres sites (8794)
-
FFmpeg : Parallel encoding with custom thread pool
13 novembre 2017, par ZeroDefectOne of the things I’m trying to achieve is parallel encoding via FFmpeg’s c API. This looks to work out of the box quite nicely ; however, I’ve changed the goal posts slightly :
In an existing application, I already have a thread pool at hand. Instead of using another thread pool via FFmpeg, I would like reuse the existing thread pool in my application. Having studied the latest FFmpeg trunk docs, it very much looks possible.
Using some FFmpeg sample code, I’ve created a sample application to demonstrate what I’m trying to achieve (see below). The sample app generates a video-only mpeg2 ts using the mp2v codec.
The problem I’m experiencing is that the custom ’thread_execute’ or ’thread_execute2’ are never invoked. This is despite the fact that the codec appears to indicate that threading is supported. Please be aware that I have not yet plumbed in the thread pool just yet. My first goal is for it to call the custom function pointer.
I’ve tried to get assistance on the FFmpeg mailing lists but to no avail.
#include <iostream>
#include <thread>
#include
#include
#include
#include <cstring>
#include <future>
extern "C"
{
#include <libavutil></libavutil>avassert.h>
#include <libavutil></libavutil>channel_layout.h>
#include <libavutil></libavutil>opt.h>
#include <libavutil></libavutil>timestamp.h>
#include <libavformat></libavformat>avformat.h>
//#include <libswscale></libswscale>swscale.h>
#include <libswresample></libswresample>swresample.h>
}
#define STREAM_DURATION 1000.0
#define STREAM_FRAME_RATE 25 /* 25 images/s */
#define STREAM_PIX_FMT AV_PIX_FMT_YUV420P /* default pix_fmt */
#define SCALE_FLAGS SWS_BICUBIC
// a wrapper around a single output AVStream
typedef struct OutputStream {
AVStream *st;
AVCodecContext *enc;
/* pts of the next frame that will be generated */
int64_t next_pts;
int samples_count;
AVFrame *frame;
AVFrame *tmp_frame;
float t, tincr, tincr2;
struct SwsContext *sws_ctx;
struct SwrContext *swr_ctx;
} OutputStream;
/////////////////////////////////////////////////////////////////////////////
// The ffmpeg variation raises compiler warnings.
char *cb_av_ts2str(char *buf, int64_t ts)
{
std::memset(buf,0,AV_TS_MAX_STRING_SIZE);
return av_ts_make_string(buf,ts);
}
/////////////////////////////////////////////////////////////////////////////
// The ffmpeg variation raises compiler warnings.
char *cb_av_ts2timestr(char *buf, int64_t ts, AVRational *tb)
{
std::memset(buf,0,sizeof(AV_TS_MAX_STRING_SIZE));
return av_ts_make_time_string(buf,ts,tb);
}
/////////////////////////////////////////////////////////////////////////////
// The ffmpeg variation raises compiler warnings.
char *cb_av_err2str(char *errbuf, size_t errbuf_size, int errnum)
{
std::memset(errbuf,0,errbuf_size);
return av_make_error_string(errbuf,errbuf_size,errnum);
}
int thread_execute(AVCodecContext* s, int (*func)(AVCodecContext *c2, void *arg2), void* arg, int* ret, int count, int size)
{
// Do it all serially for now
std::cout << "thread_execute" << std::endl;
for (int k = 0; k < count; ++k)
{
ret[k] = func(s, arg);
}
return 0;
}
int thread_execute2(AVCodecContext* s, int (*func)(AVCodecContext* c2, void* arg2, int, int), void* arg, int* ret, int count)
{
// Do it all serially for now
std::cout << "thread_execute2" << std::endl;
for (int k = 0; k < count; ++k)
{
ret[k] = func(s, arg, k, count);
}
return 0;
}
static void log_packet(const AVFormatContext *fmt_ctx, const AVPacket *pkt)
{
char s[AV_TS_MAX_STRING_SIZE];
AVRational *time_base = &fmt_ctx->streams[pkt->stream_index]->time_base;
printf("pts:%s pts_time:%s dts:%s dts_time:%s duration:%s duration_time:%s stream_index:%d\n",
cb_av_ts2str(s,pkt->pts), cb_av_ts2timestr(s,pkt->pts, time_base),
cb_av_ts2str(s,pkt->dts), cb_av_ts2timestr(s,pkt->dts, time_base),
cb_av_ts2str(s,pkt->duration), cb_av_ts2timestr(s,pkt->duration, time_base),
pkt->stream_index);
}
static int write_frame(AVFormatContext *fmt_ctx, const AVRational *time_base, AVStream *st, AVPacket *pkt)
{
/* rescale output packet timestamp values from codec to stream timebase */
av_packet_rescale_ts(pkt, *time_base, st->time_base);
pkt->stream_index = st->index;
/* Write the compressed frame to the media file. */
log_packet(fmt_ctx, pkt);
return av_interleaved_write_frame(fmt_ctx, pkt);
}
/* Add an output stream. */
static void add_stream(OutputStream *ost, AVFormatContext *oc,
AVCodec **codec,
enum AVCodecID codec_id)
{
AVCodecContext *c;
int i;
/* find the encoder */
*codec = avcodec_find_encoder(codec_id);
if (!(*codec)) {
fprintf(stderr, "Could not find encoder for '%s'\n",
avcodec_get_name(codec_id));
exit(1);
}
ost->st = avformat_new_stream(oc, NULL);
if (!ost->st) {
fprintf(stderr, "Could not allocate stream\n");
exit(1);
}
ost->st->id = oc->nb_streams-1;
c = avcodec_alloc_context3(*codec);
if (!c) {
fprintf(stderr, "Could not alloc an encoding context\n");
exit(1);
}
ost->enc = c;
switch ((*codec)->type)
{
case AVMEDIA_TYPE_AUDIO:
c->sample_fmt = (*codec)->sample_fmts ?
(*codec)->sample_fmts[0] : AV_SAMPLE_FMT_FLTP;
c->bit_rate = 64000;
c->sample_rate = 44100;
if ((*codec)->supported_samplerates) {
c->sample_rate = (*codec)->supported_samplerates[0];
for (i = 0; (*codec)->supported_samplerates[i]; i++) {
if ((*codec)->supported_samplerates[i] == 44100)
c->sample_rate = 44100;
}
}
c->channels = av_get_channel_layout_nb_channels(c->channel_layout);
c->channel_layout = AV_CH_LAYOUT_STEREO;
if ((*codec)->channel_layouts) {
c->channel_layout = (*codec)->channel_layouts[0];
for (i = 0; (*codec)->channel_layouts[i]; i++) {
if ((*codec)->channel_layouts[i] == AV_CH_LAYOUT_STEREO)
c->channel_layout = AV_CH_LAYOUT_STEREO;
}
}
c->channels = av_get_channel_layout_nb_channels(c->channel_layout);
ost->st->time_base = (AVRational){ 1, c->sample_rate };
break;
case AVMEDIA_TYPE_VIDEO:
c->codec_id = codec_id;
c->bit_rate = 400000;
/* Resolution must be a multiple of two. */
c->width = 352;
c->height = 288;
/* timebase: This is the fundamental unit of time (in seconds) in terms
* of which frame timestamps are represented. For fixed-fps content,
* timebase should be 1/framerate and timestamp increments should be
* identical to 1. */
ost->st->time_base = (AVRational){ 1, STREAM_FRAME_RATE };
c->time_base = ost->st->time_base;
c->gop_size = 12; /* emit one intra frame every twelve frames at most */
c->pix_fmt = STREAM_PIX_FMT;
if (c->codec_id == AV_CODEC_ID_MPEG2VIDEO) {
/* just for testing, we also add B-frames */
c->max_b_frames = 2;
}
if (c->codec_id == AV_CODEC_ID_MPEG1VIDEO) {
/* Needed to avoid using macroblocks in which some coeffs overflow.
* This does not happen with normal video, it just happens here as
* the motion of the chroma plane does not match the luma plane. */
c->mb_decision = 2;
}
break;
default:
break;
}
if (c->codec->capabilities & AV_CODEC_CAP_FRAME_THREADS ||
c->codec->capabilities & AV_CODEC_CAP_SLICE_THREADS)
{
if (c->codec->capabilities & AV_CODEC_CAP_FRAME_THREADS)
{
c->thread_type = FF_THREAD_FRAME;
}
if (c->codec->capabilities & AV_CODEC_CAP_SLICE_THREADS)
{
c->thread_type = FF_THREAD_SLICE;
}
c->execute = &thread_execute;
c->execute2 = &thread_execute2;
c->thread_count = 4;
// NOTE: Testing opaque.
c->opaque = (void*)0xff;
}
/* Some formats want stream headers to be separate. */
if (oc->oformat->flags & AVFMT_GLOBALHEADER)
c->flags |= AV_CODEC_FLAG_GLOBAL_HEADER;
}
/**************************************************************/
/* video output */
static AVFrame *alloc_picture(enum AVPixelFormat pix_fmt, int width, int height)
{
AVFrame *picture;
int ret;
picture = av_frame_alloc();
if (!picture)
return NULL;
picture->format = pix_fmt;
picture->width = width;
picture->height = height;
/* allocate the buffers for the frame data */
ret = av_frame_get_buffer(picture, 32);
if (ret < 0) {
fprintf(stderr, "Could not allocate frame data.\n");
exit(1);
}
return picture;
}
static void open_video(AVFormatContext *oc, AVCodec *codec, OutputStream *ost, AVDictionary *opt_arg)
{
int ret;
AVCodecContext *c = ost->enc;
//AVDictionary *opt = NULL;
//av_dict_copy(&opt, opt_arg, 0);
/* open the codec */
ret = avcodec_open2(c, codec, NULL);
//av_dict_free(&opt);
if (ret < 0) {
char s[AV_ERROR_MAX_STRING_SIZE];
fprintf(stderr, "Could not open video codec: %s\n", cb_av_err2str(s,AV_ERROR_MAX_STRING_SIZE,ret));
exit(1);
}
/* allocate and init a re-usable frame */
ost->frame = alloc_picture(c->pix_fmt, c->width, c->height);
if (!ost->frame) {
fprintf(stderr, "Could not allocate video frame\n");
exit(1);
}
/* If the output format is not YUV420P, then a temporary YUV420P
* picture is needed too. It is then converted to the required
* output format. */
ost->tmp_frame = NULL;
if (c->pix_fmt != AV_PIX_FMT_YUV420P) {
ost->tmp_frame = alloc_picture(AV_PIX_FMT_YUV420P, c->width, c->height);
if (!ost->tmp_frame) {
fprintf(stderr, "Could not allocate temporary picture\n");
exit(1);
}
}
/* copy the stream parameters to the muxer */
ret = avcodec_parameters_from_context(ost->st->codecpar, c);
if (ret < 0) {
fprintf(stderr, "Could not copy the stream parameters\n");
exit(1);
}
}
/* Prepare a dummy image. */
static void fill_yuv_image(AVFrame *pict, int frame_index,
int width, int height)
{
int x, y, i;
i = frame_index;
/* Y */
for (y = 0; y < height; y++)
for (x = 0; x < width; x++)
pict->data[0][y * pict->linesize[0] + x] = x + y + i * 3;
/* Cb and Cr */
for (y = 0; y < height / 2; y++) {
for (x = 0; x < width / 2; x++) {
pict->data[1][y * pict->linesize[1] + x] = 128 + y + i * 2;
pict->data[2][y * pict->linesize[2] + x] = 64 + x + i * 5;
}
}
}
static AVFrame *get_video_frame(OutputStream *ost)
{
AVCodecContext *c = ost->enc;
/* check if we want to generate more frames */
if (av_compare_ts(ost->next_pts, c->time_base,
STREAM_DURATION, (AVRational){ 1, 1 }) >= 0)
return NULL;
/* when we pass a frame to the encoder, it may keep a reference to it
* internally; make sure we do not overwrite it here */
if (av_frame_make_writable(ost->frame) < 0)
exit(1);
if (c->pix_fmt != AV_PIX_FMT_YUV420P) {
/* as we only generate a YUV420P picture, we must convert it
* to the codec pixel format if needed */
/*if (!ost->sws_ctx) {
ost->sws_ctx = sws_getContext(c->width, c->height,
AV_PIX_FMT_YUV420P,
c->width, c->height,
c->pix_fmt,
SCALE_FLAGS, NULL, NULL, NULL);
if (!ost->sws_ctx) {
fprintf(stderr,
"Could not initialize the conversion context\n");
exit(1);
}
}
fill_yuv_image(ost->tmp_frame, ost->next_pts, c->width, c->height);
sws_scale(ost->sws_ctx,
(const uint8_t * const *)ost->tmp_frame->data, ost->tmp_frame->linesize,
0, c->height, ost->frame->data, ost->frame->linesize);*/
} else {
fill_yuv_image(ost->frame, ost->next_pts, c->width, c->height);
}
ost->frame->pts = ost->next_pts++;
return ost->frame;
}
/*
* encode one video frame and send it to the muxer
* return 1 when encoding is finished, 0 otherwise
*/
static int write_video_frame(AVFormatContext *oc, OutputStream *ost)
{
int ret;
AVCodecContext *c;
AVFrame *frame;
int got_packet = 0;
AVPacket pkt = { 0 };
c = ost->enc;
frame = get_video_frame(ost);
if (frame)
{
ret = avcodec_send_frame(ost->enc, frame);
if (ret < 0)
{
char s[AV_ERROR_MAX_STRING_SIZE];
fprintf(stderr, "Error encoding video frame: %s\n", cb_av_err2str(s, AV_ERROR_MAX_STRING_SIZE, ret));
exit(1);
}
}
av_init_packet(&pkt);
ret = avcodec_receive_packet(ost->enc,&pkt);
if (ret < 0)
{
if (ret == AVERROR(EAGAIN)) { ret = 0; }
else
{
char s[AV_ERROR_MAX_STRING_SIZE];
fprintf(stderr, "Error receiving packet: %s\n", cb_av_err2str(s,AV_ERROR_MAX_STRING_SIZE,ret));
exit(1);
}
}
else
{
got_packet = 1;
ret = write_frame(oc, &c->time_base, ost->st, &pkt);
}
if (ret < 0) {
char s[AV_ERROR_MAX_STRING_SIZE];
fprintf(stderr, "Error while writing video frame: %s\n", cb_av_err2str(s,AV_ERROR_MAX_STRING_SIZE,ret));
exit(1);
}
return (frame || got_packet) ? 0 : 1;
}
static void close_stream(AVFormatContext *oc, OutputStream *ost)
{
avcodec_free_context(&ost->enc);
av_frame_free(&ost->frame);
av_frame_free(&ost->tmp_frame);
//sws_freeContext(ost->sws_ctx);
//swr_free(&ost->swr_ctx);
}
/**************************************************************/
/* media file output */
int main(int argc, char **argv)
{
OutputStream video_st = { 0 }, audio_st = { 0 };
const char *filename;
AVOutputFormat *fmt;
AVFormatContext *oc;
AVCodec /**audio_codec,*/ *video_codec;
int ret;
int have_video = 0, have_audio = 0;
int encode_video = 0, encode_audio = 0;
AVDictionary *opt = NULL;
int i;
/* Initialize libavcodec, and register all codecs and formats. */
av_register_all();
avformat_network_init();
if (argc < 2) {
printf("usage: %s output_file\n"
"API example program to output a media file with libavformat.\n"
"This program generates a synthetic audio and video stream, encodes and\n"
"muxes them into a file named output_file.\n"
"The output format is automatically guessed according to the file extension.\n"
"Raw images can also be output by using '%%d' in the filename.\n"
"\n", argv[0]);
return 1;
}
filename = argv[1];
for (i = 2; i+1 < argc; i+=2) {
if (!strcmp(argv[i], "-flags") || !strcmp(argv[i], "-fflags"))
av_dict_set(&opt, argv[i]+1, argv[i+1], 0);
}
const char *pfilename = filename;
/* allocate the output media context */
avformat_alloc_output_context2(&oc, NULL, "mpegts", pfilename);
if (!oc) {
printf("Could not deduce output format from file extension: using MPEG.\n");
avformat_alloc_output_context2(&oc, NULL, "mpeg", pfilename);
}
if (!oc)
return 1;
fmt = oc->oformat;
/* Add the audio and video streams using the default format codecs
* and initialize the codecs. */
if (fmt->video_codec != AV_CODEC_ID_NONE) {
add_stream(&video_st, oc, &video_codec, fmt->video_codec);
have_video = 1;
encode_video = 1;
}
/*if (fmt->audio_codec != AV_CODEC_ID_NONE) {
add_stream(&audio_st, oc, &audio_codec, fmt->audio_codec);
have_audio = 1;
encode_audio = 1;
}*/
/* Now that all the parameters are set, we can open the audio and
* video codecs and allocate the necessary encode buffers. */
if (have_video)
open_video(oc, video_codec, &video_st, opt);
//if (have_audio)
// open_audio(oc, audio_codec, &audio_st, opt);
av_dump_format(oc, 0, pfilename, 1);
/* open the output file, if needed */
if (!(fmt->flags & AVFMT_NOFILE)) {
ret = avio_open(&oc->pb, pfilename, AVIO_FLAG_WRITE);
if (ret < 0) {
char s[AV_ERROR_MAX_STRING_SIZE];
fprintf(stderr, "Could not open '%s': %s\n", pfilename,
cb_av_err2str(s,AV_ERROR_MAX_STRING_SIZE,ret));
return 1;
}
}
/* Write the stream header, if any. */
ret = avformat_write_header(oc, &opt);
if (ret < 0) {
char s[AV_ERROR_MAX_STRING_SIZE];
fprintf(stderr, "Error occurred when opening output file: %s\n",
cb_av_err2str(s,AV_ERROR_MAX_STRING_SIZE,ret));
return 1;
}
while (encode_video || encode_audio) {
/* select the stream to encode */
if (encode_video &&
(!encode_audio || av_compare_ts(video_st.next_pts, video_st.enc->time_base,
audio_st.next_pts, audio_st.enc->time_base) <= 0)) {
encode_video = !write_video_frame(oc, &video_st);
} else {
//encode_audio = !write_audio_frame(oc, &audio_st);
}
//std::this_thread::sleep_for(std::chrono::milliseconds(35));
}
/* Write the trailer, if any. The trailer must be written before you
* close the CodecContexts open when you wrote the header; otherwise
* av_write_trailer() may try to use memory that was freed on
* av_codec_close(). */
av_write_trailer(oc);
/* Close each codec. */
if (have_video)
close_stream(oc, &video_st);
if (have_audio)
close_stream(oc, &audio_st);
if (!(fmt->flags & AVFMT_NOFILE))
/* Close the output file. */
avio_closep(&oc->pb);
/* free the stream */
avformat_free_context(oc);
return 0;
}
//
</future></cstring></thread></iostream>Environment :
- Ubuntu Zesty (17.04)
- FFmpeg version 3.2.4 (via package manager)
- gcc 6.3 (C++)
-
ffmpeg unable to get duration/bitrate of remote gif
17 février, par Peter XiaI'm trying to get the duration of a gif.


The command
ffmpeg -i https://cdn.7tv.app/emote/01F6MZGCNG000255K4X1K7NTHR/4x.gif

gives

Duration: N/A, start: 0.000000, bitrate: N/A

However if i download the file and pass it in

ffmpeg -i 4x.gif

it gives :

Duration: 00:00:07.92, start: 0.000000, bitrate: 1225 kb/s

The issue seems limited only to gifs on 7tv site.


- 

- It works for other sites. (example :
ffmpeg -i https://c.tenor.com/ULCY5B996-oAAAAd/tenor.gif). - It also works for other encodings of that image (exmaple
ffmpeg -i https://cdn.7tv.app/emote/01F6MZGCNG000255K4X1K7NTHR/4x.avif)






Here is the HTTP response header from 7tv site of that gif :


HTTP/2 200 
content-type: image/gif
content-length: 1213725
x-7tv-cache-hits: 37527
x-7tv-cache: hit
age: 228365
cache-control: public, max-age=604800, s-maxage=86400, immutable
alt-svc: h3=":443"; ma=2592000
x-7tv-cdn-pod: cdn-ssprq
x-7tv-cdn-node: cdn-1
server: SevenTV
vary: origin, access-control-request-method, access-control-request-headers
access-control-allow-origin: *
access-control-expose-headers: *
date: Sun, 16 Feb 2025 20:47:28 GMT


Can someone help me understand ? Something spcecific to this site is causing ffmpeg to behave differently ?


- It works for other sites. (example :
-
How to improve web camera streaming latency to v4l2loopback device with ffmpeg ?
11 mars, par Made by MosesI'm trying to stream my iPhone camera to my PC on LAN.


What I've done :


- 

-
HTTP server with html page and streaming script :


I use WebSockets here and maybe WebRTC is better choice but it seems like network latency is good enough






async function beginCameraStream() {
 const mediaStream = await navigator.mediaDevices.getUserMedia({
 video: { facingMode: "user" },
 });

 websocket = new WebSocket(SERVER_URL);

 websocket.onopen = () => {
 console.log("WS connected");

 const options = { mimeType: "video/mp4", videoBitsPerSecond: 1_000_000 };
 mediaRecorder = new MediaRecorder(mediaStream, options);

 mediaRecorder.ondataavailable = async (event) => {
 // to measure latency I prepend timestamp to the actual video bytes chunk
 const timestamp = Date.now();
 const timestampBuffer = new ArrayBuffer(8);
 const dataView = new DataView(timestampBuffer);
 dataView.setBigUint64(0, BigInt(timestamp), true);
 const data = await event.data.bytes();

 const result = new Uint8Array(data.byteLength + 8);
 result.set(new Uint8Array(timestampBuffer), 0);
 result.set(data, 8);

 websocket.send(result);
 };

 mediaRecorder.start(100); // Collect 100ms chunks
 };
}


- 

-
Server to process video chunks






import { serve } from "bun";
import { Readable } from "stream";

const V4L2LOOPBACK_DEVICE = "/dev/video10";

export const setupFFmpeg = (v4l2device) => {
 // prettier-ignore
 return spawn("ffmpeg", [
 '-i', 'pipe:0', // Read from stdin
 '-pix_fmt', 'yuv420p', // Pixel format
 '-r', '30', // Target 30 fps
 '-f', 'v4l2', // Output format
 v4l2device, // Output to v4l2loopback device
 ]);
};

export class FfmpegStream extends Readable {
 _read() {
 // This is called when the stream wants more data
 // We push data when we get chunks
 }
}

function main() {
 const ffmpeg = setupFFmpeg(V4L2LOOPBACK_DEVICE);
 serve({
 port: 8000,
 fetch(req, server) {
 if (server.upgrade(req)) {
 return; // Upgraded to WebSocket
 }
 },
 websocket: {
 open(ws) {
 console.log("Client connected");
 const stream = new FfmpegStream();
 stream.pipe(ffmpeg?.stdin);

 ws.data = {
 stream,
 received: 0,
 };
 },
 async message(ws, message) {
 const view = new DataView(message.buffer, 0, 8);
 const ts = Number(view.getBigUint64(0, true));
 ws.data.received += message.byteLength;
 const chunk = new Uint8Array(message.buffer, 8, message.byteLength - 8);

 ws.data.stream.push(chunk);

 console.log(
 [
 `latency: ${Date.now() - ts} ms`,
 `chunk: ${message.byteLength}`,
 `total: ${ws.data.received}`,
 ].join(" | "),
 );
 },
 },
 });
}

main();


After I try to open the v4l2loopback device


cvlc v4l2:///dev/video10


picture is delayed for at least 1.5 sec which is unacceptable for my project.


Thoughts :


- 

- Problem doesn't seems to be with network latency




latency: 140 ms | chunk: 661 Bytes | total: 661 Bytes
latency: 206 ms | chunk: 16.76 KB | total: 17.41 KB
latency: 141 ms | chunk: 11.28 KB | total: 28.68 KB
latency: 141 ms | chunk: 13.05 KB | total: 41.74 KB
latency: 199 ms | chunk: 11.39 KB | total: 53.13 KB
latency: 141 ms | chunk: 16.94 KB | total: 70.07 KB
latency: 139 ms | chunk: 12.67 KB | total: 82.74 KB
latency: 142 ms | chunk: 13.14 KB | total: 95.88 KB


150ms is actually too much for 15KB on LAN but there can some issue with my router


- 

- As far as I can tell it neither ties to ffmpeg throughput :




Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'pipe:0':
 Metadata:
 major_brand : iso5
 minor_version : 1
 compatible_brands: isomiso5hlsf
 creation_time : 2025-03-09T17:16:49.000000Z
 Duration: 00:00:01.38, start:
0.000000, bitrate: N/A
 Stream #0:0(und): Video: h264 (Baseline) (avc1 / 0x31637661), yuvj420p(pc), 1280x720, 4012 kb/s, 57.14 fps, 29.83 tbr, 600 tbn, 1200 tbc (default)
 Metadata:
 rotate : 90
 creation_time : 2025-03-09T17:16:49.000000Z
 handler_name : Core Media Video
 Side data:
 displaymatrix: rotation of -90.00 degrees

Stream mapping:
 Stream #0:0 -> #0:0 (h264 (native) -> rawvideo (native))

[swscaler @ 0x55d8d0b83100] deprecated pixel format used, make sure you did set range correctly

Output #0, video4linux2,v4l2, to '/dev/video10':
 Metadata:
 major_brand : iso5
 minor_version : 1
 compatible_brands: isomiso5hlsf
 encoder : Lavf58.45.100

Stream #0:0(und): Video: rawvideo (I420 / 0x30323449), yuv420p, 720x1280, q=2-31, 663552 kb/s, 60 fps, 60 tbn, 60 tbc (default)
 Metadata:
 encoder : Lavc58.91.100 rawvideo
 creation_time : 2025-03-09T17:16:49.000000Z
 handler_name : Core Media Video
 Side data:
 displaymatrix: rotation of -0.00 degrees

frame= 99 fps=0.0 q=-0.0 size=N/A time=00:00:01.65 bitrate=N/A dup=50 drop=0 speed=2.77x
frame= 137 fps=114 q=-0.0 size=N/A time=00:00:02.28 bitrate=N/A dup=69 drop=0 speed=1.89x
frame= 173 fps= 98 q=-0.0 size=N/A time=00:00:02.88 bitrate=N/A dup=87 drop=0 speed=1.63x
frame= 210 fps= 86 q=-0.0 size=N/A time=00:00:03.50 bitrate=N/A dup=105 drop=0 speed=1.44x
frame= 249 fps= 81 q=-0.0 size=N/A time=00:00:04.15 bitrate=N/A dup=125 drop=0 speed=1.36
frame= 279 fps= 78 q=-0.0 size=N/A time=00:00:04.65 bitrate=N/A dup=139 drop=0 speed=1.31x


- 

-
I also tried to write the video stream directly to
video.mp4file and immediately open it withvlcbut it only can be successfully opened after 1.5 sec.

-
I've tried to use OBS v4l2 input source instead of vlc but the latency is the same








Update №1


When i try to stream actual
.mp4file toffmpegit works almost immediately with 0.2sec delay to spin up the ffmpeg itself :

cat video.mp4 | ffmpeg -re -i pipe:0 -pix_fmt yuv420p -f v4l2 /dev/video10 & ; sleep 0.2 && cvlc v4l2:///dev/video10


So the problem is apparently with streaming process


-
Syndiquer tout le site
