The NvMedia nvmimg_enc sample application demonstrates how to use the NvMedia image encode API to encode H.264/H.265 bitstreams based on the NVENC hardware engine.

The application consumes raw images in one of the following:

It produces compressed elementary streams in one of the following formats:

nvmimg_enc can run in blackbox mode for the number of seconds specified. When set, the current number of seconds bitstream is saved in the output bitstream file. The number of seconds is specified in the command line.

This topic describes the nvmimg_enc architecture and flow.

Picture buffers must be in block linear (T124/T210) format. Pitch-linear input data is not supported due to inefficiency in the memory accesses.

Picture buffers must also be in NV12 format. The picture dimensions of the encoded streams are always in multiples of X pixels.

Where X is:

If the input needs cropping, it is cropped at the right and bottom of the picture. If the input pictures horizontal/vertical are not X aligned, the application software must verify the padding on the right/bottom side to make it X aligned.

Follow the steps in this topic to run the sample.

Default configuration files are available at:

The configuration file structure consists of parameters assigned with values, groups of parameters or sections, and comments. For more information, see Configuration File Syntax and Semantics.

The following shows the command syntax:

The following table describes the required command line options.

The following table describes the required command line options.

 

This topic explains how to perform commonly performed tasks.

The encoding is performed using parameters supplied in the specified configuration file. The base configuration file specifies the input and output file information. However, it is more convenient to use a "specific" configuration file for these parameters and pass them through the command line using -p option.

In blackbox mode, nvmimg_enc saves the current number of seconds bitstream in the output bitstream file. The number of seconds is specified in the command line.

In black box recording mode, nvmimg_enc forces the following encode parameters:

The settings guarantee that each GOP bitstream is decoded independently. The GOP size and IDR period can be set to half second encode time, or other values. The user application can choose values which fits the use case as desired.

The encoding is performed using parameters supplied in enc_h264_sample.cfg and enc_h26x_aqiyo_specific.cfg files. If a parameter is present in both files, its value is taken from the specific configuration file enc_h26x_aqiyo_specific.cfg.

Default configuration fiels are available at:

The configuration file structure consists of parameters assigned with values, groups of parameters or sections, and comments.

Comments begin with a pound sign (#). The text that appears after the pound sign to the end of the line is considered to be a comment and is not parsed by the configuration file parser.

Each parameter must be set on a separate line. A parameter line consistes of the following tokens:

After these tokens, you can add a comment.

For example:

Setting an unknown parameter in a configuration file does not cause a failure, but this parameter is not to be used. A Mal-structured parameter line causes a failure.

Sections are instances of groups of parameters. Sections make the configuration file less complicated and avoids parameter repetition. Some parameters appear in more than one context and must be set for each context separately. By having several sections, or just one section for these parameters, you can point to same section from different contexts. This is helpful when using the same values in different contexts.

For example, rate control parameters must be set for encoder initialization and can be set for every frame separately. Instead of repeating rate control parameters in every context, create several instances of RC_Params and set in every context the section number to be used:

*EPRateControlSectionIndex - set with the rate control parameters section number used for encoder initialization.

Available section types include:

Each section must be preceded with a line: [<section name> <section number>]. For example:

Parameters that specify the length on an array, such as ExplicitFrameInvervalPatternLength, ExplicitFrameInvervalPattern, are not required to be set. The default array size is used if the length is not specified. The default array size is 1000.

The following table describes the general configuration parameters.

The following table describes the encode configuration parameters.

The following table describes the quantization configuration parameters.

The following table describes the rate control configuration parameters.

The following table describes the per-frame encode configuration parameters.

The following table describes the H.264 encode configuration parameters.

The following table describes the H264 VUI configuration parameters.

The following table describes the H.264 payload configuration parameters.

The following table describes the H264 per-frame encode configuration parameters. These are in addition to Per-Frame Encode Configuration Parameters. EncodePicH264_Params parameters group in Configuration file. These must be sent on a per frame basis.

The following table describes the H.265 configuration parameters.

The following table describes the H.265 VUI configuration parameters.

The following table describes the H265 payload configuration parameters. Payload parameters group in the Configuration file.

The following table describes the H265 per-frame encode configuration parameters. EncodePicH265_Params parameters group in the Configuration file. These must be sent on a per frame basis.