
Recherche avancée
Médias (1)
-
Bug de détection d’ogg
22 mars 2013, par
Mis à jour : Avril 2013
Langue : français
Type : Video
Autres articles (20)
-
Submit bugs and patches
13 avril 2011Unfortunately a software is never perfect.
If you think you have found a bug, report it using our ticket system. Please to help us to fix it by providing the following information : the browser you are using, including the exact version as precise an explanation as possible of the problem if possible, the steps taken resulting in the problem a link to the site / page in question
If you think you have solved the bug, fill in a ticket and attach to it a corrective patch.
You may also (...) -
Encoding and processing into web-friendly formats
13 avril 2011, parMediaSPIP automatically converts uploaded files to internet-compatible formats.
Video files are encoded in MP4, Ogv and WebM (supported by HTML5) and MP4 (supported by Flash).
Audio files are encoded in MP3 and Ogg (supported by HTML5) and MP3 (supported by Flash).
Where possible, text is analyzed in order to retrieve the data needed for search engine detection, and then exported as a series of image files.
All uploaded files are stored online in their original format, so you can (...) -
Contribute to translation
13 avril 2011You can help us to improve the language used in the software interface to make MediaSPIP more accessible and user-friendly. You can also translate the interface into any language that allows it to spread to new linguistic communities.
To do this, we use the translation interface of SPIP where the all the language modules of MediaSPIP are available. Just subscribe to the mailing list and request further informantion on translation.
MediaSPIP is currently available in French and English (...)
Sur d’autres sites (4109)
-
Blog series part 2 : How to increase engagement of your website visitors, and turn them into customers
8 septembre 2020, par Joselyn Khor — Analytics Tips, Marketing -
Can't compile C library with C++ code using g++
13 novembre 2019, par shaystI’m trying to create a C++ program that embeds FFMPEG functionality.
To do that I took one FFMPEG example and recompiled it as is using g++ (only adding extern "C" where needed).
Compilation is successful, but linking fails for undefined symbols.cc -I/usr/include/x86_64-linux-gnu -Wall -g -fPIC -c -o bin/decode_video.o decode_video.cpp
cc -Wl,--export-dynamic,--no-undefined -L /usr/lib/x86_64-linux-gnu/ -shared -lavdevice -lavutil -lavcodec bin/decode_video.o -o decode_video.so
bin/decode_video.o: In function `decode(AVCodecContext*, AVFrame*, AVPacket*, char const*)':
/home/admin1/ffmpeg_examples/decode_video.cpp:60: undefined reference to `avcodec_send_packet'
/home/admin1/ffmpeg_examples/decode_video.cpp:67: undefined reference to `avcodec_receive_frame'
bin/decode_video.o: In function `main':
/home/admin1/ffmpeg_examples/decode_video.cpp:108: undefined reference to `av_packet_alloc'
/home/admin1/ffmpeg_examples/decode_video.cpp:116: undefined reference to `avcodec_find_decoder'
/home/admin1/ffmpeg_examples/decode_video.cpp:122: undefined reference to `av_parser_init'
/home/admin1/ffmpeg_examples/decode_video.cpp:128: undefined reference to `avcodec_alloc_context3'
/home/admin1/ffmpeg_examples/decode_video.cpp:139: undefined reference to `avcodec_open2'
/home/admin1/ffmpeg_examples/decode_video.cpp:150: undefined reference to `av_frame_alloc'
/home/admin1/ffmpeg_examples/decode_video.cpp:165: undefined reference to `av_parser_parse2'
/home/admin1/ffmpeg_examples/decode_video.cpp:184: undefined reference to `av_parser_close'
/home/admin1/ffmpeg_examples/decode_video.cpp:185: undefined reference to `avcodec_free_context'
/home/admin1/ffmpeg_examples/decode_video.cpp:186: undefined reference to `av_frame_free'
/home/admin1/ffmpeg_examples/decode_video.cpp:187: undefined reference to `av_packet_free'checking nm I see that there’s no name mangling in action so extern C seems to work well :
nm bin/decode_video.o
U avcodec_alloc_context3
U avcodec_find_decoder
U avcodec_free_context
U avcodec_open2
U avcodec_receive_frame
U avcodec_send_packet
U av_frame_alloc
U av_frame_free
U av_packet_alloc
U av_packet_free
U av_parser_close
U av_parser_init
U av_parser_parse2
U exit
U fclose
U feof
U fflush
U fopen
U fprintf
U fread
U fwrite
U _GLOBAL_OFFSET_TABLE_
000000000000026f T main
U memset
U printf
U snprintf
U __stack_chk_fail
U stderr
U stdout
00000000000000a3 t _ZL6decodeP14AVCodecContextP7AVFrameP8AVPacketPKc
0000000000000000 t _ZL8pgm_savePhiiiPcchecking the library, for one of the ’missing’ symbols, I can see it is implemented
nm /usr/lib/x86_64-linux-gnu/libavcodec.a | grep avcodec_send_packet
00000000000033e0 T avcodec_send_packet
U avcodec_send_packetWhen compiling in C it works perfectly (without extern C of course) which makes me wonder what am I missing ?
Below find FFMPEG example code for reference (decode_video.cpp) :
#include
#include
#include
extern "C"
{
#include <libavcodec></libavcodec>avcodec.h>
}
#define INBUF_SIZE 4096
static void pgm_save(unsigned char *buf, int wrap, int xsize, int ysize,
char *filename)
{
FILE *f;
int i;
f = fopen(filename,"w");
fprintf(f, "P5\n%d %d\n%d\n", xsize, ysize, 255);
for (i = 0; i < ysize; i++)
fwrite(buf + i * wrap, 1, xsize, f);
fclose(f);
}
static void decode(AVCodecContext *dec_ctx, AVFrame *frame, AVPacket *pkt,
const char *filename)
{
char buf[1024];
int ret;
ret = avcodec_send_packet(dec_ctx, pkt);
if (ret < 0) {
fprintf(stderr, "Error sending a packet for decoding\n");
exit(1);
}
while (ret >= 0) {
ret = avcodec_receive_frame(dec_ctx, frame);
if (ret == AVERROR(EAGAIN) || ret == AVERROR_EOF)
return;
else if (ret < 0) {
fprintf(stderr, "Error during decoding\n");
exit(1);
}
printf("saving frame %3d\n", dec_ctx->frame_number);
fflush(stdout);
/* the picture is allocated by the decoder. no need to
free it */
snprintf(buf, sizeof(buf), "%s-%d", filename, dec_ctx->frame_number);
pgm_save(frame->data[0], frame->linesize[0],
frame->width, frame->height, buf);
}
}
int main(int argc, char **argv)
{
const char *filename, *outfilename;
const AVCodec *codec;
AVCodecParserContext *parser;
AVCodecContext *c= NULL;
FILE *f;
AVFrame *frame;
uint8_t inbuf[INBUF_SIZE + AV_INPUT_BUFFER_PADDING_SIZE];
uint8_t *data;
size_t data_size;
int ret;
AVPacket *pkt;
if (argc <= 2) {
fprintf(stderr, "Usage: %s <input file="file" /> <output file="file">\n"
"And check your input file is encoded by mpeg1video please.\n", argv[0]);
exit(0);
}
filename = argv[1];
outfilename = argv[2];
pkt = av_packet_alloc();
if (!pkt)
exit(1);
/* set end of buffer to 0 (this ensures that no overreading happens for damaged MPEG streams) */
memset(inbuf + INBUF_SIZE, 0, AV_INPUT_BUFFER_PADDING_SIZE);
/* find the MPEG-1 video decoder */
codec = avcodec_find_decoder(AV_CODEC_ID_MPEG1VIDEO);
if (!codec) {
fprintf(stderr, "Codec not found\n");
exit(1);
}
parser = av_parser_init(codec->id);
if (!parser) {
fprintf(stderr, "parser not found\n");
exit(1);
}
c = avcodec_alloc_context3(codec);
if (!c) {
fprintf(stderr, "Could not allocate video codec context\n");
exit(1);
}
/* For some codecs, such as msmpeg4 and mpeg4, width and height
MUST be initialized there because this information is not
available in the bitstream. */
/* open it */
if (avcodec_open2(c, codec, NULL) < 0) {
fprintf(stderr, "Could not open codec\n");
exit(1);
}
f = fopen(filename, "rb");
if (!f) {
fprintf(stderr, "Could not open %s\n", filename);
exit(1);
}
frame = av_frame_alloc();
if (!frame) {
fprintf(stderr, "Could not allocate video frame\n");
exit(1);
}
while (!feof(f)) {
/* read raw data from the input file */
data_size = fread(inbuf, 1, INBUF_SIZE, f);
if (!data_size)
break;
/* use the parser to split the data into frames */
data = inbuf;
while (data_size > 0) {
ret = av_parser_parse2(parser, c, &pkt->data, &pkt->size,
data, data_size, AV_NOPTS_VALUE, AV_NOPTS_VALUE, 0);
if (ret < 0) {
fprintf(stderr, "Error while parsing\n");
exit(1);
}
data += ret;
data_size -= ret;
if (pkt->size)
decode(c, frame, pkt, outfilename);
}
}
/* flush the decoder */
decode(c, frame, NULL, outfilename);
fclose(f);
av_parser_close(parser);
avcodec_free_context(&c);
av_frame_free(&frame);
av_packet_free(&pkt);
return 0;
}
</output> -
How to convert H264 RTP stream from PCAP to a playable video file
7 novembre 2017, par yooshaI have captured stream of H264 in PCAP files and trying to create media files from the data. The container is not important (avi,mp4,mkv,…).
When I’m using videosnarf or rtpbreak (combined with python code that adds 00 00 00 01 before each packet) and then ffmpeg, the result is OK only if the input frame rate is constant (or near constant). However, when the input is vfr, the result plays too fast (and on same rare cases too slow).
For example :videosnarf -i captured.pcap –c
ffmpeg -i H264-media-1.264 output.aviAfter doing some investigation of the issue I believe now that since the videosnarf (and rtpbreak) are removing the RTP header from the packets, the timestamp is lost and ffmpeg is referring to the input data as cbr.
- I would like to know if there is a way to pass (on a separate file ?)
the timestamps vector or any other information to ffmpeg so the
result will be created correctly ? - Is there any other way I can take the data out of the PCAP file and play it or convert it and then play it ?
- Since all work is done in Python, any suggestion of libraries/modules that can help with the work (even if requires some codding) is welcome as well.
Note : All work is done offline, no limitations on the output. It can be cbr/vbr, any playable container and transcoding. The only "limitation" I have : it should all run on linux…
Thanks
YSome additional information :
Since the nothing provides the FFMPEG with the timestamp data, i decided to try a different approach : skip videosnarf and use Python code to pipe the packets directly to ffmpeg (using the "-f -i -" options) but then it refuses to accept it unless I provide an SDP file...
How do I provide the SDP file ? is it an additional input file ? ("-i config.sdp")The following code is an unsuccessful try doing the above :
import time
import sys
import shutil
import subprocess
import os
import dpkt
if len(sys.argv) < 2:
print "argument required!"
print "txpcap <pcap file="file">"
sys.exit(2)
pcap_full_path = sys.argv[1]
ffmp_cmd = ['ffmpeg','-loglevel','debug','-y','-i','109c.sdp','-f','rtp','-i','-','-na','-vcodec','copy','p.mp4']
ffmpeg_proc = subprocess.Popen(ffmp_cmd,stdout = subprocess.PIPE,stdin = subprocess.PIPE)
with open(pcap_full_path, "rb") as pcap_file:
pcapReader = dpkt.pcap.Reader(pcap_file)
for ts, data in pcapReader:
if len(data) < 49:
continue
ffmpeg_proc.stdin.write(data[42:])
sout, err = ffmpeg_proc.communicate()
print "stdout ---------------------------------------"
print sout
print "stderr ---------------------------------------"
print err
</pcap>In general this will pipe the packets from the PCAP file to the following command :
ffmpeg -loglevel debug -y -i 109c.sdp -f rtp -i - -na -vcodec copy p.mp4
SDP file : [RTP includes dynamic payload type # 109, H264]
v=0
o=- 0 0 IN IP4 ::1
s=No Name
c=IN IP4 ::1
t=0 0
a=tool:libavformat 53.32.100
m=video 0 RTP/AVP 109
a=rtpmap:109 H264/90000
a=fmtp:109
packetization-mode=1 ;profile-level-id=64000c ;sprop-parameter-sets=Z2QADKwkpAeCP6wEQAAAAwBAAAAFI8UKkg==,aMvMsiw= ;
b=AS:200Results :
ffmpeg version 0.10.2 Copyright (c) 2000-2012 the FFmpeg developers
built on Mar 20 2012 04:34:50 with gcc 4.4.6 20110731 (Red Hat
4.4.6-3) configuration : —prefix=/usr —libdir=/usr/lib64 —shlibdir=/usr/lib64 —mandir=/usr/share/man —enable-shared —enable-runtime-cpudetect —enable-gpl —enable-version3 —enable-postproc —enable-avfilter —enable-pthreads —enable-x11grab —enable-vdpau —disable-avisynth —enable-frei0r —enable-libopencv —enable-libdc1394 —enable-libdirac —enable-libgsm —enable-libmp3lame —enable-libnut —enable-libopencore-amrnb —enable-libopencore-amrwb —enable-libopenjpeg —enable-librtmp —enable-libschroedinger —enable-libspeex —enable-libtheora —enable-libvorbis —enable-libvpx —enable-libx264 —enable-libxavs —enable-libxvid —extra-cflags=’-O2 -g -pipe -Wall -Wp,-D_FORTIFY_SOURCE=2 -fexceptions -fstack-protector —param=ssp-buffer-size=4 -m64 -mtune=generic -fPIC’ —disable-stripping libavutil 51. 35.100 / 51. 35.100 libavcodec 53. 61.100 / 53. 61.100 libavformat 53. 32.100
/ 53. 32.100 libavdevice 53. 4.100 / 53. 4.100
libavfilter 2. 61.100 / 2. 61.100 libswscale 2. 1.100
/ 2. 1.100 libswresample 0. 6.100 / 0. 6.100
libpostproc 52. 0.100 / 52. 0.100 [sdp @ 0x15c0c00] Format sdp
probed with size=2048 and score=50 [sdp @ 0x15c0c00] video codec set
to : h264 [NULL @ 0x15c7240] RTP Packetization Mode : 1 [NULL @
0x15c7240] RTP Profile IDC : 64 Profile IOP : 0 Level : c [NULL @
0x15c7240] Extradata set to 0x15c78e0 (size : 36) !error,_recognition
separate : 1 ; 1 [h264 @ 0x15c7240] error,_recognition combined : 1 ;
10001 [sdp @ 0x15c0c00] decoding for stream 0 failed [sdp @
0x15c0c00] Could not find codec parameters (Video : h264) [sdp @
0x15c0c00] Estimating duration from bitrate, this may be inaccurate
109c.sdp : could not find codec parameters Traceback (most recent
call last) : File "./ffpipe.py", line 26, in
ffmpeg_proc.stdin.write(data[42 :]) IOError : [Errno 32] Broken pipe(forgive the mass above, the editor keep on complaining about code that is not indented OK ??)
I’m working on this issue for days... any help/suggestion/hint will be appreciated.
- I would like to know if there is a way to pass (on a separate file ?)