directshow_mpeg2_video_encoder

nanocosmos MPEG-2 Video Encoder Filter

DirectShow Filter / Module

nanocosmos MPEG-2 Video Encoder\ Module Name: nmpeg2enc.ax

DirectShow Connectivity

The input is accepting connections to video source, capture and decoder filters matching the following media types:

Major types:

• MEDIATYPE_Video

Subtypes:

• MEDIASUBTYPE_YV12,
• MEDIASUBTYPE_I420,
• MEDIASUBTYPE_YUY2,
• MEDIASUBTYPE_UYVY,
• MEDIASUBTYPE_HDYC,
• MEDIASUBTYPE_RGB24,
• MEDIASUBTYPE_RGB32,
• MEDIASUBTYPE_ARGB32,
• MEDIASUBTYPE_RGB565,

Formats:

• FORMAT_VideoInfo
• FORMAT_VideoInfo2

The output supports these media types:

Major types:

• MEDIATYPE_Video

Subtypes:

• MEDIASUBTYPE_MPEG2_VIDEO,
• MEDIASUBTYPE_mpgv

Formats:

• FORMAT_MPEG2_VIDEO,
• FORMAT_NONE

Configuration

The encoding configuration may be set by using either the property page or the COM Interface INanoCodecOpts as declared in header file INanoCodecOpts.h .

// Filter GUID
// {2327A344-BECC-4f4f-89C6-DABDC5143832}
DEFINE_GUID(CLSID_NANO_MPEG2_ENCODER, 0x2327a344, 0xbecc, 0x4f4f, 0x89, 0xc6, 0xda, 0xbd, 0xc5, 0x14, 0x38, 0x32);

// Property Page GUID
// {8A84396A-277A-4835-9EB5-719863194DC9}
DEFINE_GUID(CLSID_NANO_MPEG2_ENCODER_PROPPAGE, 0x8a84396a, 0x277a, 0x4835, 0x9e, 0xb5, 0x71, 0x98, 0x63, 0x19, 0x4d, 0xc9);

// Configuration Interface GUID
// {698E0F57-B828-4c40-8867-095FF49F77D6}
DEFINE_GUID(IID_INanoCodecOpts, 0x698e0f57, 0xb828, 0x4c40, 0x88, 0x67, 0x9, 0x5f, 0xf4, 0x9f, 0x77, 0xd6);

// Configuration interface ICodecProp
// {0F817204-82C8-4c12-884A-F45FB2F33A6E}
DEFINE_GUID(IID_ICodecProp, 0xf817204, 0x82c8, 0x4c12, 0x88, 0x4a, 0xf4, 0x5f, 0xb2, 0xf3, 0x3a, 0x6e);

// ICodecProp: IID_nanoPeg_LicenseString
// type: BSTR / Unicode string
// Set license string to unlock filter
// {1788F0B0-5985-4a19-B7FE-8AAC1BFC14B3}
DEFINE_GUID(IID_nanoPeg_LicenseString, 0x1788f0b0, 0x5985, 0x4a19, 0xb7, 0xfe, 0x8a, 0xac, 0x1b, 0xfc, 0x14, 0xb3);

Setting the license to unlock filter

The filter can be unlocked either through a license key entry in the windows registry or by setting the license key through COM interface ICodecProp::SetProperty with the property IID_nanoPeg_LicenseString as first parameter. The second license parameter has to be a wide/unicode string!

Common Encoder Settings

Parameter	Default values	Description
profile, level	Main Profile, Main Level	MPEG-2 Profile and Level
base_video.bitrate_kb	Profile and Level dependend	Video Bitrate in kBits/second
base_video.resolution.width	0 - use input width	Picture Coding Width
base_video.resolution.height	0 - use input height	Picture Coding Height
chroma_format_idc	0 - I420, 1 - I422	[0,1] Chroma Format
rate_method	0 - CBR, 1 - VBR	[0,1] Rate Control Mode
distance_i	12	Intra Frame Distance / GOP len.
distance_p	3	P Frame Distance

Configuration through INanoCodecOpts interface

• Version check by calling //GetCodecOptsVersion//// //(optional)
• Instanciating a parameter structure of type //MPDX4_MPEG2EncoderParams//
• Initializing the parameter struct by calling //InitCodecOptions// will set all parameters to default values for the selected profile and level
• Setting custom values for resolution and bitrate
• Applying settings by calling //SetCodecOptions//

Here a code snippet without error handling to show configuration for IMX 50 format:

#include "mpeg2_enc_params.h"

HRESULT hr = S_OK;

// Query INanoCodecOpts interface from IBaseFilter interface
// of MPEG-2 Encoder filter
CComQIPtr<INanoCodecOpts> pNanoCodecOpts = pBaseFilter;

MPDX4_MPEG2EncoderParams mpeg2EncParams;
memset(&mpeg2EncParams, 0, sizeof(MPDX4_MPEG2EncoderParams));

// Set desired profile and level values
mpeg2EncParams.profile = MPDX4_MPEG2_PROFILE_422IMX;
mpeg2EncParams.level = MPDX4_MPEG2_LEVEL_MAIN;

// Intialize the parameter struct according to profile and level set
hr = pNanoCodecOpts->InitCodecOptions((MPDX4_BaseCodecOpts*) &mpeg2EncParams, INANOCODECOPTS_VERSION);

// Set custom parameter values
// Bitrate
mpeg2EncParams.base_video.bitrate_kb = 50000; // IMX 50
// If resize is needed
mpeg2EncParams.base_video.resolution.width = 720;
mpeg2EncParams.base_video.resolution.height = 608;

// Apply settings and finish configuration
hr = pNanoCodecOpts->SetCodecOptions((MPDX4_BaseCodecOpts*) &mpeg2EncParams, INANOCODECOPTS_VERSION);

Configuration through DirectShow filter property page

The filter's property page offers a subset of encoding parameters, containing the most important options.

Debug-Log Configuration Registry Settings

Key: HKEY_CURRENT_USER\Software\DebugNano\nmpeg2enc.ax

File name

Sets the output file name. The folder must already exist.

• Value name: LogToFile
• Value type: REG_SZ / String
• Valid values: a valid output file name to enable file logging or an empty string

Logging level

A higher value increases the amount of logging messages sent, and messages get more detailed.

• Value name: TRACE
• Value type: REG_DWORD
• Valid values:
  • 0 - minimal logging
  • …
  • 9 - maximal logging