[Ffmpeg-devel] Re: I want to resize getted frame from movie file.

QuickTime ffmpeg
Sat Jul 30 03:05:12 CEST 2005


Dear:

> 
> I want to watch fixed display size from movie file. (eg. 640x480)
>  I'm trying to use img_resample function.
>  I don't know what i do before calling img_resample_init function.
>  something following line.
> 
> if(packet.stream_index == m_nVideoStream)
> {
> // decoding next frame.
> bytesDecoded = avcodec_decode_video(m_pCodecCtx, m_pFrame, &frameFinished,
> packet.data, packet.size);
> 
> if(frameFinished)
> {
>  img_convert((AVPicture *)m_pFrameRGB, PIX_FMT_RGB24, (AVPicture*)m_pFrame,
> m_pCodecCtx->pix_fmt, m_pCodecCtx->width, m_pCodecCtx->height); // m_pFrame
> has YUV frame
>  ImgReSampleContext *s;
> s = img_resample_init( 640, 480, width, height); // initialize resample

you'd better use img_resample_full_init(...) to initialize the
resample context !

> img_resample(s, m_pic, (AVPicture *)m_pFrameRGB); // error occur

How do you initialize the "m_pic"?
you should fill "m_pic" with yuv420(640x480) layout buffer firstly
There is an important note that img_resample(...) is only happy with
YUV420 pix format,but not RGB

>  img_resample_close(s);
>  Jeon,Chang-Min
>  Thanks.

Take care!





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