Libvpx API Error Codes Explained

This article provides a quick reference guide to the most common error codes returned by the libvpx API, the open-source video codec library used for VP8 and VP9 encoding and decoding. Understanding these return values—which are defined under the vpx_codec_err_t enumeration—helps developers quickly debug media pipeline failures, configuration mismatches, and memory allocation issues during video processing.

Common libvpx Error Codes

The libvpx library uses specific return codes to indicate the success or failure of API functions. Below are the primary error codes you will encounter when working with the library:

• VPX_CODEC_OK (0): The operation completed successfully. This is the expected return value for all successful API calls, indicating that the encoder or decoder processed the command without issue.
• VPX_CODEC_ERROR (1): A generic error. This is a fallback code used when an unspecified error occurs that does not map to a more specific error category. When this occurs, developers often need to check internal library logs or verify the input state.
• VPX_CODEC_MEM_ERROR (2): Out of memory. This error indicates that libvpx failed to allocate the necessary system memory required for internal buffers, frame structures, or codec state initialization.
• VPX_CODEC_ABI_MISMATCH (3): Application Binary Interface mismatch. This happens when the version of the libvpx headers (vpx/vpx_codec.h) used to compile your application does not match the version of the actual binary library (.so, .dll, or .dylib) loaded at runtime.
• VPX_CODEC_INVAL_PARAM (4): Invalid parameter. This is one of the most common runtime errors, triggered when a function receives an argument that is out of range, null, or structurally incorrect. Examples include setting an unsupported resolution, a negative bitrate, or an invalid frame rate in the configuration structure.
• VPX_CODEC_UNSUP_BITSTREAM (5): Unsupported bitstream. This is returned by the decoder when it encounters an input bitstream that it does not know how to parse, which can happen if you pass non-VP8/VP9 data or data encoded with an unsupported profile.
• VPX_CODEC_UNSUP_FEATURE (6): Unsupported feature. This indicates that the requested codec feature (such as specific multi-threading configurations, scaling algorithms, or bit-depth modes) is not supported by the compiled library or the specific codec algorithm in use.
• VPX_CODEC_CORRUPT_FRAME (7): Corrupt frame. The decoder returns this when it detects data corruption, missing packets, or decoding errors in the input compressed frame that prevent it from rendering a complete or safe image.
• VPX_CODEC_INVALID_ABILITY (8): Codec lacks capability. This error occurs when you attempt to query or configure a capability (using vpx_codec_control) that the instantiated codec does not support—for example, attempting to apply encoder-specific controls to a decoder instance.

How to Retrieve Error Details

When an API call returns an error code other than VPX_CODEC_OK, you can retrieve a human-readable explanation of the error using the following utility functions:

• vpx_codec_err_to_string(): Pass the returned vpx_codec_err_t code to this function to receive a brief, static string describing the error type.
• vpx_codec_error(): Pass the codec context pointer (vpx_codec_ctx_t*) to this function to retrieve a detailed string representation of the last error that occurred on that specific context.
• vpx_codec_error_detail(): This function provides a highly specific, context-dependent error message (if available) explaining exactly why the codec failed, which is highly useful for debugging parameter validation issues.