GstBuffer *buf = GST_PAD_PROBE_INFO_BUFFER (info); GstH264NalUnitType nal_type = GST_H264_NAL_UNIT_TYPE (GST_BUFFER_DATA (buf)[0]);提示error: subscripted value is neither array nor pointer nor vector应该如何修改

这个错误通常是因为缺少包含相应头文件的声明。你需要包含 `gst/codecparsers/gsth264parser.h` 头文件来解决这个问题，该头文件定义了 `gst_h264_nal_unit_type_get_type()` 和 `GST_H264_NAL_UNIT_TYPE()` 宏，使你能够使用 `GST_H264_NAL_UNIT_TYPE()` 宏来获取 `GstH264NalUnitType` 类型的值。修改后的示例代码如下：

#include <gst/gst.h>
#include <gst/codecparsers/gsth264parser.h>

static GstPadProbeReturn
sps_pps_probe_cb (GstPad * pad, GstPadProbeInfo * info, gpointer user_data)
{
  GstBuffer *buf = GST_PAD_PROBE_INFO_BUFFER (info);
  GstH264NalUnitType nal_type = GST_H264_NAL_UNIT_TYPE (GST_BUFFER_DATA (buf)[0]);

  if (nal_type == GST_H264_NAL_SPS) {
    // This is an SPS unit
    guint8 *sps = GST_BUFFER_DATA (buf);
    guint sps_len = GST_BUFFER_SIZE (buf);
    // Do something with the SPS data
  } else if (nal_type == GST_H264_NAL_PPS) {
    // This is a PPS unit
    guint8 *pps = GST_BUFFER_DATA (buf);
    guint pps_len = GST_BUFFER_SIZE (buf);
    // Do something with the PPS data
  }

  return GST_PAD_PROBE_OK;
}

int main(int argc, char *argv[]) {
  GstElement *pipeline, *source, *h264parse;
  GstBus *bus;
  GstMessage *msg;

  /* Initialize GStreamer */
  gst_init(&argc, &argv);

  /* Create the elements */
  source = gst_element_factory_make("filesrc", "source");
  h264parse = gst_element_factory_make("h264parse", "h264parse");

  /* Create the pipeline */
  pipeline = gst_pipeline_new("test-pipeline");

  /* Build the pipeline */
  gst_bin_add_many(GST_BIN(pipeline), source, h264parse, NULL);
  gst_element_link_many(source, h264parse, NULL);

  /* Set the input file */
  g_object_set(G_OBJECT(source), "location", "test.h264", NULL);

  /* Register the SPS/PPS probe */
  GstPad *h264parse_src_pad = gst_element_get_static_pad(h264parse, "src");
  gst_pad_add_probe(h264parse_src_pad, GST_PAD_PROBE_TYPE_BUFFER, sps_pps_probe_cb, NULL, NULL);

  /* Start playing */
  gst_element_set_state(pipeline, GST_STATE_PLAYING);

  /* Wait until error or end of the stream */
  bus = gst_element_get_bus(pipeline);
  msg = gst_bus_timed_pop_filtered(bus, GST_CLOCK_TIME_NONE, GST_MESSAGE_ERROR | GST_MESSAGE_EOS);
  if (msg != NULL) {
    gst_message_unref(msg);
  }

  /* Free resources */
  gst_object_unref(bus);
  gst_element_set_state(pipeline, GST_STATE_NULL);
  gst_object_unref(pipeline);
  return 0;
}

请确保你已经正确安装了 GStreamer 和相关的插件，以及包含了正确的头文件和库文件。