Gstreamer and V4L2 Formats - 2020.2 English

H.264/H.265 Video Codec Unit v1.2 Solutions LogiCORE IP Product Guide (PG252)

Document ID
PG252
Release Date
2020-11-24
Version
2020.2 English

The Gstreamer and V4L2 Formats are described in this section.

  • These formats signify the memory layout of pixels. It applies at the encoder input and the decoder output side.
  • The encoder needs to know the memory layout of pixel at input side for reading the raw data, so the corresponding video format needs to be specified at encoder sink pad using caps.
  • For the decoder, you can specify the format to be used to write the pixel in memory by specifying the corresponding Gstreamer video format using caps at decoder source pad.
  • When the format is not supported between two elements, the cap negotiation fails and Gstreamer returns an error. In that case, you can use the video convert element to perform software conversion from one format to another.

The following table shows the GStreamer and V4L2 related formats that are supported.

Table 1. Gstreamer and V4L2 Formats
Pixel Format V4L2 GStreamer
YUV 420 8-bit V4L2_PIX_FMT_NV12 GST_VIDEO_FORMAT_NV12
YUV 420 10-bit V4L2_PIX_FMT_XV15 GST_VIDEO_FORMAT_NV12_10LE32
YUV 422 8-bit V4L2_PIX_FMT_NV16 GST_VIDEO_FORMAT_NV16
YUV 422 10-bit V4L2_PIX_FMT_XV20 GST_VIDEO_FORMAT_NV16_10LE32
Note:
  1. The fourcc codes are the last four characters of v4L2 pixel formats (for example, GREY/XY10…).
  2. Y_Only 8-bit and Y_Only 10-bit are supported only at the control software layer for the encoder and decoder.