mpeg2encoptions.cc

来自「Motion JPEG编解码器源代码」· CC 代码 · 共 555 行 · 第 1/2 页

    if( preserve_B && Bgrp_size == 0 )
    {
		mjpeg_error_exit1("Preserving I/P frame spacing is impossible for still encoding" );
    }

	if( preserve_B && 
		( min_GOP_size % Bgrp_size != 0 ||
		  max_GOP_size % Bgrp_size != 0 )
		)
	{
		mjpeg_error("Preserving I/P frame spacing is impossible if min and max GOP sizes are" );
		mjpeg_error_exit1("Not both divisible by %d", Bgrp_size );
	}

	switch( format )
	{
	case MPEG_FORMAT_SVCD_STILL :
	case MPEG_FORMAT_SVCD_NSR :
	case MPEG_FORMAT_SVCD : 
		if( aspect_ratio != 2 && aspect_ratio != 3 )
			mjpeg_error_exit1("SVCD only supports 4:3 and 16:9 aspect ratios");
		if( svcd_scan_data )
		{
			mjpeg_warn( "Generating dummy SVCD scan-data offsets to be filled in by \"vcdimager\"");
			mjpeg_warn( "If you're not using vcdimager you may wish to turn this off using -d");
		}
		break;
	}
	return nerr;
}

bool MPEG2EncOptions::SetFormatPresets( const MPEG2EncInVidParams &strm )
{
    int nerr = 0;
    in_img_width = strm.horizontal_size;
    in_img_height = strm.vertical_size;

	switch( format  )
	{
	case MPEG_FORMAT_MPEG1 :  /* Generic MPEG1 */
		mjpeg_info( "Selecting generic MPEG1 output profile");
		if( video_buffer_size == 0 )
			video_buffer_size = 46;
		if (bitrate == 0)
			bitrate = 1151929;
		break;

	case MPEG_FORMAT_VCD :
		mpeg = 1;
		bitrate = 1151929;
		video_buffer_size = 46;
        	preserve_B = true;
        	Bgrp_size = 3;
        	min_GOP_size = 9;
		max_GOP_size = norm == 'n' ? 18 : 15;
		mjpeg_info("VCD default options selected");
		
	case MPEG_FORMAT_VCD_NSR : /* VCD format, non-standard rate */
		mjpeg_info( "Selecting VCD output profile");
		mpeg = 1;
		svcd_scan_data = 0;
		seq_hdr_every_gop = 1;
		if (bitrate == 0)
			bitrate = 1151929;
		if (video_buffer_size == 0)
			video_buffer_size = 46 * bitrate / 1151929;
        	if (seq_length_limit == 0 )
            		seq_length_limit = 700;
        	if (nonvid_bitrate == 0)
            		nonvid_bitrate = 230;
		break;
		
	case  MPEG_FORMAT_MPEG2 : 
		mjpeg_info( "Selecting generic MPEG2 output profile");
		mpeg = 2;
		if (!force_cbr && quant == 0)
			quant = 8;
		if (video_buffer_size == 0)
			video_buffer_size = 230;
		break;

	case MPEG_FORMAT_SVCD :
		mjpeg_info("SVCD standard settings selected");
		if (nonvid_bitrate == 0)
		   /* 224 kbps for audio + around 2% of 2788800 bits */
		   nonvid_bitrate = 288; 
		if (bitrate == 0 || bitrate > 2788800 - nonvid_bitrate * 1000)
		   bitrate = 2788800 - nonvid_bitrate * 1000;
		max_GOP_size = norm == 'n' ? 18 : 15;
		video_buffer_size = 230;

	case  MPEG_FORMAT_SVCD_NSR :		/* Non-standard data-rate */
		mjpeg_info( "Selecting SVCD output profile");
		mpeg = 2;
		if (!force_cbr && quant == 0)
			quant = 8;
		if( svcd_scan_data == -1 )
			svcd_scan_data = 1;
		if (video_buffer_size == 0)
			video_buffer_size = 230;
		if( min_GOP_size == -1 )
            		min_GOP_size = 9;
        	seq_hdr_every_gop = 1;
        	if (seq_length_limit == 0)
            		seq_length_limit = 700;
        	if (nonvid_bitrate == 0)
            		nonvid_bitrate = 230;
        	break;

	case MPEG_FORMAT_VCD_STILL :
		mjpeg_info( "Selecting VCD Stills output profile");
		mpeg = 1;
		quant = 0;	/* We want to try and hit our size target */

		/* We choose a generous nominal bit-rate as there's only 
		   one frame per sequence ;-).  It *is* too small to fill 
		   the frame-buffer in less than one PAL/NTSC frame
		   period though...*/
		bitrate = 8000000;

		/* Now we select normal/hi-resolution based on the input stream
		   resolution. 
		*/
		
		if( in_img_width == 352 && 
			(in_img_height == 240 || in_img_height == 288 ) )
		{
			/* VCD normal resolution still */
			if( still_size == 0 )
				still_size = 30*1024;
			if( still_size < 20*1024 || still_size > 42*1024 )
			{
				mjpeg_error_exit1( "VCD normal-resolution stills must be >= 20KB and <= 42KB each");
			}
			/* VBV delay encoded normally */
			vbv_buffer_still_size = 46*1024;
			video_buffer_size = 46;
			pad_stills_to_vbv_buffer_size = 0;
		}
		else if( in_img_width == 704 &&
				 (in_img_height == 480 || in_img_height == 576) )
		{
			/* VCD high-resolution stills: only these use vbv_delay
			 to encode picture size...
			*/
			if( still_size == 0 )
				still_size = 125*1024;
			if( still_size < 46*1024 || still_size > 220*1024 )
			{
				mjpeg_error_exit1( "VCD normal-resolution stills should be >= 46KB and <= 220KB each");
			}
			vbv_buffer_still_size = still_size;
			video_buffer_size = 224;
			pad_stills_to_vbv_buffer_size = 1;			
		}
		else
		{
			mjpeg_error("VCD normal resolution stills must be 352x288 (PAL) or 352x240 (NTSC)");
			mjpeg_error_exit1( "VCD high resolution stills must be 704x576 (PAL) or 704x480 (NTSC)");
		}
		seq_hdr_every_gop = 1;
		seq_end_every_gop = 1;
		min_GOP_size = 1;
		max_GOP_size = 1;
		break;

	case MPEG_FORMAT_SVCD_STILL :
		mjpeg_info( "Selecting SVCD Stills output profile");
		mpeg = 2;
		quant = 0;	/* We want to try and hit our size target */

		/* We choose a generous nominal bitrate as there's only one 
		   frame per sequence ;-). It *is* too small to fill the 
		   frame-buffer in less than one PAL/NTSC frame 
		   period though...
		*/
		bitrate = 2500000;
		video_buffer_size = 230;
		vbv_buffer_still_size = 220*1024;
		pad_stills_to_vbv_buffer_size = 0;

		/* Now we select normal/hi-resolution based on the input stream
		   resolution. 
		*/
		
		if( in_img_width == 480 && 
			(in_img_height == 480 || in_img_height == 576 ) )
		{
			mjpeg_info( "SVCD normal-resolution stills selected." );
			if( still_size == 0 )
				still_size = 90*1024;
		}
		else if( in_img_width == 704 &&
				 (in_img_height == 480 || in_img_height == 576) )
		{
			mjpeg_info( "SVCD high-resolution stills selected." );
			if( still_size == 0 )
				still_size = 125*1024;
		}
		else
		{
			mjpeg_error("SVCD normal resolution stills must be 480x576 (PAL) or 480x480 (NTSC)");
			mjpeg_error_exit1( "SVCD high resolution stills must be 704x576 (PAL) or 704x480 (NTSC)");
		}

		if( still_size < 30*1024 || still_size > 200*1024 )
		{
			mjpeg_error_exit1( "SVCD resolution stills must be >= 30KB and <= 200KB each");
		}


		seq_hdr_every_gop = 1;
		seq_end_every_gop = 1;
		min_GOP_size = 1;
		max_GOP_size = 1;
		break;

	case MPEG_FORMAT_DVD :
	case MPEG_FORMAT_DVD_NAV :
		mjpeg_info( "Selecting DVD output profile");
		mpeg = 2;
		if (bitrate == 0)
			bitrate = 7500000;
        	if (video_buffer_size == 0)
            		video_buffer_size = 230;
		if (!force_cbr && quant == 0)
			quant = 8;
		seq_hdr_every_gop = 1;
		break;
	}


    /*
     * At this point the command line arguments have been processed, the format (-f)
     * selection has had a chance to set the bitrate.  IF --cbr was used and we
     * STILL do not have a bitrate set then declare an error because a Constant
     * Bit Rate of 0 makes no sense (most of the time CBR doesn't either ... ;))
     */
     if (force_cbr && bitrate == 0)
        {
        nerr++;
        mjpeg_error("--cbr used but no bitrate set with -b or -f!");
        }


    switch( mpeg )
    {
    case 1 :
        if( min_GOP_size == -1 )
            min_GOP_size = 12;
        if( max_GOP_size == -1 )
            max_GOP_size = 12;
        break;
    case 2:
        if( min_GOP_size == -1 )
            min_GOP_size = 9;
        if( max_GOP_size == -1 )
            max_GOP_size = (norm == 'n' ? 18 : 15);
        break;
    }
	if( svcd_scan_data == -1 )
		svcd_scan_data = 0;
	nerr += InferStreamDataParams(strm);
	nerr += CheckBasicConstraints();

	return nerr != 0;
}

/* 
 * Local variables:
 *  c-file-style: "stroustrup"
 *  tab-width: 4
 *  indent-tabs-mode: nil
 * End:
 */