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Sur d’autres sites (9185)

  • a lot of GREEN Color at YUV420p —> RGB in OpenGL 2.0 Shader on iOS

    25 octobre 2012, par 이형근

    I want to make a movie player for iOS using ffmpeg and OpenGL ES 2.0
    but I have some problem. Output RGB image has a lot of GREEN color.
    This is code and images

    • 480x320 width & height :
    • 512x512 Texture width & height

    I got a YUV420p row data from ffmpeg AVFrame.

        for (int i = 0, nDataLen = 0; i < 3; i++) {
    
        int nShift = (i == 0) ? 0 : 1;
    
        uint8_t *pYUVData = (uint8_t *)_frame->data[i];
    
        for (int j = 0; j < (mHeight >> nShift); j++) {
    
            memcpy(&pData->pOutBuffer[nDataLen], pYUVData, (mWidth >> nShift));
    
            pYUVData += _frame->linesize[i];
    
            nDataLen += (mWidth >> nShift);
    
        }
    
    }

    and prepare texture for Y, U & V channel.

    //: U Texture
    
    if (sampler1Texture) glDeleteTextures(1, &sampler1Texture);
    

    
    glActiveTexture(GL_TEXTURE1);
    
    glGenTextures(1, &sampler1Texture);
    
    glBindTexture(GL_TEXTURE_2D, sampler1Texture);
    

    
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
    
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
    
    // This is necessary for non-power-of-two textures
    
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
    
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
    
    glEnable(GL_TEXTURE_2D);
    

    
    glTexImage2D(GL_TEXTURE_2D, 
    
                 0, 
    
                 GL_LUMINANCE, 
    
                 texW / 2, 
    
                 texH / 2, 
    
                 0, 
    
                 GL_LUMINANCE, 
    
                 GL_UNSIGNED_BYTE,
    
                 NULL);
    

    
    //: V Texture
    
    if (sampler2Texture) glDeleteTextures(1, &sampler2Texture);
    

    
    glActiveTexture(GL_TEXTURE2);
    
    glGenTextures(1, &sampler2Texture);
    
    glBindTexture(GL_TEXTURE_2D, sampler2Texture);
    

    
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
    
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
    
    // This is necessary for non-power-of-two textures
    
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
    
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
    
    glEnable(GL_TEXTURE_2D);
    

    
    glTexImage2D(GL_TEXTURE_2D, 
    
                 0, 
    
                 GL_LUMINANCE, 
    
                 texW / 2, 
    
                 texH / 2, 
    
                 0, 
    
                 GL_LUMINANCE,
    
                 GL_UNSIGNED_BYTE,
    
                 NULL);
    

    
    //: Y Texture
    
    if (sampler0Texture) glDeleteTextures(1, &sampler0Texture);
    

    
    glActiveTexture(GL_TEXTURE0);
    
    glGenTextures(1, &sampler0Texture);
    
    glBindTexture(GL_TEXTURE_2D, sampler0Texture);
    

    
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
    
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
    
    // This is necessary for non-power-of-two textures
    
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
    
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
    
    glEnable(GL_TEXTURE_2D);
    

    
    glTexImage2D(GL_TEXTURE_2D, 
    
                 0, 
    
                 GL_LUMINANCE, 
    
                 texW, 
    
                 texH, 
    
                 0, 
    
                 GL_LUMINANCE,
    
                 GL_UNSIGNED_BYTE, 
    
                 NULL);

    Rendering part is below.

    int _idxU = mFrameW * mFrameH;
    
int _idxV = _idxU + (_idxU / 4);
    

    
// U data
    
glActiveTexture(GL_TEXTURE1);
    
glBindTexture(GL_TEXTURE_2D, sampler1Texture);
    
glUniform1i(sampler1Uniform, 1);
    

    
glTexSubImage2D(
    
                GL_TEXTURE_2D, 
    
                0, 
    
                0, 
    
                0, 
    
                mFrameW / 2,            // source width
    
                mFrameH / 2,            // source height
    
                GL_LUMINANCE,
    
                GL_UNSIGNED_BYTE, 
    
                &_frameData[_idxU]);
    

    
// V data
    
glActiveTexture(GL_TEXTURE2);
    
glBindTexture(GL_TEXTURE_2D, sampler2Texture);
    
glUniform1i(sampler2Texture, 2);
    

    
glTexSubImage2D(
    
                GL_TEXTURE_2D, 
    
                0, 
    
                0, 
    
                0, 
    
                mFrameW / 2,            // source width
    
                mFrameH / 2,            // source height
    
                GL_LUMINANCE,
    
                GL_UNSIGNED_BYTE,
    
                &_frameData[_idxV]);
    

    
// Y data
    
glActiveTexture(GL_TEXTURE0);
    
glBindTexture(GL_TEXTURE_2D, sampler0Texture);
    
glUniform1i(sampler0Uniform, 0);
    

    
glTexSubImage2D(
    
                GL_TEXTURE_2D, 
    
                0, 
    
                0, 
    
                0, 
    
                mFrameW,            // source width
    
                mFrameH,            // source height
    
                GL_LUMINANCE,
    
                GL_UNSIGNED_BYTE,
    
                _frameData);

    Vertex Shader & Fragment Shader is below.

    attribute vec4 Position;
    
attribute vec2 TexCoordIn;
    

    
varying vec2 TexCoordOut;
    
varying vec2 TexCoordOut_UV;
    

    
uniform mat4 Projection;
    
uniform mat4 Modelview;
    

    
void main()
    
{
    
    gl_Position = Projection * Modelview * Position;
    
    TexCoordOut = TexCoordIn;
    
}
    

    

    

    
uniform sampler2D sampler0; // Y Texture Sampler
    
uniform sampler2D sampler1; // U Texture Sampler
    
uniform sampler2D sampler2; // V Texture Sampler
    

    
varying highp vec2 TexCoordOut;
    

    
void main()
    
{
    
    highp float y = texture2D(sampler0, TexCoordOut).r;
    
    highp float u = texture2D(sampler2, TexCoordOut).r - 0.5;
    
    highp float v = texture2D(sampler1, TexCoordOut).r - 0.5;
    

    
    //y = 0.0;
    
    //u = 0.0;
    
    //v = 0.0;
    

    
    highp float r = y + 1.13983 * v;
    
    highp float g = y - 0.39465 * u - 0.58060 * v;
    
    highp float b = y + 2.03211 * u;
    

    
    gl_FragColor = vec4(r, g, b, 1.0);
    
}

    Y Texture (Grayscale) is correct but U & V has a lot of Green Color.
    So final RGB image (Y+U+V) has a lot of GREEN Color.
    What's the problem ?

    Please help.
    thanks.

  • Fragmented MP4 has wrong duration in Windows Media Player

    3 février 2020, par Expressingx

    I’m streaming video from a camera to a file using ffmpeg. The case to use Fragmented MP4 is that there can be sudden power off and lose the video. I’ve configured the fragments to be at least 30 secs and this is how much the Windows Media Player reports for the duration even if its 2 hours long, after that it keeps streaming the video but is not seekable after the 30th second. How can be that fixed ?

    ffmpeg -c copy -movflags frag_keyframe+separate_moof+omit_tfhd_offset -min_frag_duration 30000000 -bsf:a aac_adtstoasc \ out.mp4

    If I use -movflags frag_keyframe+empty_moov then the video is not seekable at all and no duration reported.

    I aim for seekable video with correct duration both on VLC/Windows Media Player

    Version of ffmpeg : 3.3.4

  • Smooth FPS change via FFMPEG

    2 juin 2020, par RazrFalcon

    I have a 240FPS video from GoPro and I want to slow down it to 30FPS linearly. For this I'm using :

    



    ffmpeg -i raw.mp4 -filter_complex "[v:0]setpts='lerp(2,8,T/5)*PTS" -r 30 output.mp4


    



    * 5 is video duration in seconds

    



    The problem is that the resulting video stutters pretty heavily. But if I use a fixed setpts, like setpts=8*PTS, then everything is fine.

    



    How to make smooth FPS transition via FFMPEG ?

    


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