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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 (...) -
Des sites réalisés avec MediaSPIP
2 mai 2011, parCette page présente quelques-uns des sites fonctionnant sous MediaSPIP.
Vous pouvez bien entendu ajouter le votre grâce au formulaire en bas de page. -
Selection of projects using MediaSPIP
2 mai 2011, parThe examples below are representative elements of MediaSPIP specific uses for specific projects.
MediaSPIP farm @ Infini
The non profit organizationInfini develops hospitality activities, internet access point, training, realizing innovative projects in the field of information and communication technologies and Communication, and hosting of websites. It plays a unique and prominent role in the Brest (France) area, at the national level, among the half-dozen such association. Its members (...)
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Have problems using FFMPEG to save RGB image sequence to .mp4
28 septembre 2021, par ClubsI render some images with OpenGL and need to compose them into a video file. Each of the images is a sequence of uint8_t values representing a sRGB color component (image array looks like ...rgbrgbrgb...)



I know very little about video processing and have no experience with ffmpeg libraries at all. I made a little test program using these sources as reference :



https://ffmpeg.org/doxygen/trunk/encode_video_8c-example.html



How to convert RGB from YUV420p for ffmpeg encoder ?



The test program is supposed to make a video about growing green vertical stripe. I'm just trying to figure out how to make a video using some source of raw RGB data.



Here is my code :



#include <iostream>
#include <vector>
#include <algorithm>

extern "C" {
 #include <libavcodec></libavcodec>avcodec.h>
 #include <libavutil></libavutil>opt.h>
 #include <libavutil></libavutil>imgutils.h>
 #include <libswscale></libswscale>swscale.h>
}

static void encode( AVCodecContext* enc_ctx,
 AVFrame* frame, AVPacket* pkt,
 FILE* outfile )
{
 int ret;
 ret = avcodec_send_frame(enc_ctx, frame);
 if (ret < 0) {
 std::cerr << "Error sending a frame for encoding\n";
 return;
 }
 while (ret >= 0) {
 ret = avcodec_receive_packet(enc_ctx, pkt);
 if (ret == AVERROR(EAGAIN) || ret == AVERROR_EOF)
 return;
 else if (ret < 0) {
 fprintf(stderr, "Error during encoding\n");
 exit(1);
 }
 fwrite(pkt->data, 1, pkt->size, outfile);
 av_packet_unref(pkt);
 }
}

static constexpr int w = 1920, h = 1080;
static constexpr float fps = 20.f, time = 5.f;
static constexpr int nFrames = static_cast<int>(fps * time);
static std::vector imageRGB(w * h * 3, 0);

static void UpdateImageRGB()
{
 static int d = 50;
 imageRGB.assign(w * h * 3, 0);
 for (int i = 0; i < h; ++i)
 for ( int j = std::max(0, w / 2 - d);
 j < std::min(w, w / 2 + d);
 ++j )
 {
 imageRGB[(w * i + j) * 3 + 0] = 50;
 imageRGB[(w * i + j) * 3 + 1] = 200;
 imageRGB[(w * i + j) * 3 + 2] = 50;
 }
 d += 5;
}

int main()
{
 int ret = 0;
 auto filename = "test.mp4";

 auto codec = avcodec_find_encoder(AV_CODEC_ID_H264);
 if (!codec) {
 std::cerr << "Codec \"x.264\" not found\n";
 return 1;
 }
 auto c = avcodec_alloc_context3(codec);
 if (!c) {
 std::cerr << "Could not allocate video codec context\n";
 return 1;
 }
 auto pkt = av_packet_alloc();
 if (!pkt) return 1;

 // 1.8 bits / (pixel * frame)
 c->bit_rate = static_cast(1.8f * w * h * fps);
 /* resolution must be a multiple of two */
 c->width = w;
 c->height = h;
 /* frames per second */
 c->time_base = AVRational{ 1, static_cast<int>(fps) };
 c->framerate = AVRational{ static_cast<int>(fps), 1 };

 c->gop_size = 10;
 c->max_b_frames = 1;
 c->pix_fmt = AV_PIX_FMT_YUV420P;
 av_opt_set(c->priv_data, "preset", "slow", 0);
 av_opt_set(c->priv_data, "preset", "slow", 0);

 ret = avcodec_open2(c, codec, NULL);
 if (ret < 0) {
 char str[AV_ERROR_MAX_STRING_SIZE];
 std::cerr << "Could not open codec: "
 << av_make_error_string(str, AV_ERROR_MAX_STRING_SIZE, ret)
 << "\n";
 return 1;
 }

 FILE * f;
 fopen_s(&f, filename, "wb");
 if (!f) {
 std::cerr << "Could not open " << filename << '\n';
 return 1;
 }

 auto frame = av_frame_alloc();
 if (!frame) {
 std::cerr << "Could not allocate video frame\n";
 return 1;
 }
 frame->format = c->pix_fmt;
 frame->width = c->width;
 frame->height = c->height;
 ret = av_frame_get_buffer(frame, 0);
 if (ret < 0) {
 std::cerr << stderr, "Could not allocate the video frame data\n";
 return 1;
 }

 SwsContext* ctx = sws_getContext( w, h, AV_PIX_FMT_RGB24,
 w, h, AV_PIX_FMT_YUV420P,
 0, 0, 0, 0 );

 for (int i = 0; i < nFrames; i++)
 {
 ret = av_frame_make_writable(frame);
 UpdateImageRGB();
 static const uint8_t* rgbData[1] = { &imageRGB[0] };
 static constexpr int rgbLinesize[1] = { 3 * w };
 sws_scale( ctx, rgbData, rgbLinesize, 0, h,
 frame->data, frame->linesize );
 frame->pts = i;
 /* encode the image */
 encode(c, frame, pkt, f);
 }
 encode(c, NULL, pkt, f);

 fclose(f);
 avcodec_free_context(&c);
 av_frame_free(&frame);
 av_packet_free(&pkt);
 return 0;
}
</int></int></int></algorithm></vector></iostream>


The program generates 33.9k video file with further console output :



[libx264 @ 0000020c18681800] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX FMA3 BMI2 AVX2
[libx264 @ 0000020c18681800] profile High, level 5.0, 4:2:0, 8-bit
[libx264 @ 0000020c18681800] frame I:11 Avg QP: 0.00 size: 639
[libx264 @ 0000020c18681800] frame P:74 Avg QP: 0.32 size: 174
[libx264 @ 0000020c18681800] frame B:15 Avg QP: 2.26 size: 990
[libx264 @ 0000020c18681800] consecutive B-frames: 70.0% 30.0%
[libx264 @ 0000020c18681800] mb I I16..4: 100.0% 0.0% 0.0%
[libx264 @ 0000020c18681800] mb P I16..4: 0.6% 0.0% 0.0% P16..4: 2.1% 0.0% 0.0% 0.0% 0.0% skip:97.3%
[libx264 @ 0000020c18681800] mb B I16..4: 0.1% 0.0% 0.0% B16..8: 0.6% 0.0% 0.0% direct: 0.6% skip:98.7% L0:39.8% L1:60.2% BI: 0.0%
[libx264 @ 0000020c18681800] final ratefactor: -46.47
[libx264 @ 0000020c18681800] 8x8 transform intra:0.0%
[libx264 @ 0000020c18681800] direct mvs spatial:0.0% temporal:100.0%
[libx264 @ 0000020c18681800] coded y,uvDC,uvAC intra: 0.0% 0.1% 0.1% inter: 0.0% 0.1% 0.1%
[libx264 @ 0000020c18681800] i16 v,h,dc,p: 99% 0% 1% 0%
[libx264 @ 0000020c18681800] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu: 0% 0% 100% 0% 0% 0% 0% 0% 0%
[libx264 @ 0000020c18681800] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 46% 0% 54% 0% 0% 0% 0% 0% 0%
[libx264 @ 0000020c18681800] i8c dc,h,v,p: 96% 1% 3% 0%
[libx264 @ 0000020c18681800] Weighted P-Frames: Y:0.0% UV:0.0%
[libx264 @ 0000020c18681800] ref P L0: 70.2% 0.0% 29.8% 0.0% 0.0%
[libx264 @ 0000020c18681800] kb/s:55.61



- 

- "Media Player Classic" on Windows plays this video but the time slider doesn't move, and the video cannot be fast-forwarded to some frame
- VLC cannot play the video at all. It launches, shows me VLC logo, and time slider (which is unusually big) jumps from left to right, not responding to my clicks
- If I set time = 0.05 to make a video of only 1 frame, I cannot play it even with "Media Player Classic". I want to make an algorithm to convert the arbitrary number of raw RGB images into the video files, even if there's only one image, and with arbitrary image size (that is, width and height may be odd).
- As I said, I don't really understand what am I doing. There are low-level codec settings in lines 83-84. Are they all right ?
- Do I have to manually set a bit rate (line 75) ? Shouldn't it be calculated automatically by the codec ?












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extract audio using ffmpeg and save wav files
7 mai 2018, par jameshwart lopezffmpeg has a way to extract video images using the following command
ffmpeg -i "video.avi" -vf fps=30 "images/frame_%09d.png" -hide_bannerIs there a way in ffmpeg to extract or cut audios into smaller chunks the same way that is done on the above command but the difference is it will create an audio file not an image file.
I tried the following but it only creates a wav file.
ffmpeg -i "video.avi" -vf fps=30 "images/frame_%09d.wav" -hide_banner -
How to save sequence of images in `000` pattern [on hold]
17 mars 2014, par Maged E Williami try to make video out of images, but i only know how to do that with one image like this :
ffmpeg -f image2 -i C:\Secret\17_03_2014_11_31_34_AM\000.jpeg -r 12 -s 683x384 C:\Secret\17_03_2014_11_31_34_AM\foo.avinow here's my images looks like :
i tried this :
ffmpeg -f image2 -i C:\Secret\17_03_2014_11_31_34_AM\-%03d.jpeg -r 12 -s 683x384 C:\Secret\17_03_2014_11_31_34_AM\foo.avibut it says :
could find no file with path 'C:\Secret\17_03_2014_11_31_34_AM\-%03d.jpeg' and index in the range 0-4
C:\Secret\17_03_2014_11_31_34_AM\-%03d.jpeg: no such file directory
>any help with converting all of them ?
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