Don't understand error

[Chris Tapp]

On 28 Mar 2014, at 17:04, Tim Müller <tim at centricular.com> wrote:

> On Fri, 2014-03-28 at 09:36 -0700, Kenairod wrote:
> 
> Hi,
> 
>> Well, here is the C code I'm using to create the Pipeline.
>> 
>> const gchar * serverIpAddress;
> 
> Try initialising it to someting, e.g. "" or "FIXME".

This bit does that:

       const char *temp = (*env)->GetStringUTFChars(env, ipAddress, 0);
       serverIpAddress = temp;
       (*env)->ReleaseStringUTFChars(env, ipAddress, temp);

But:
  1) That puts UTF8 into char with the risk that the encoding might not be compatible (probably ok here);
  2) But... Doesn't ReleaseStringUTFChars then release the string before it gets used?

> 
>> // .....
>> 
>> /* Main method for the native code. This is executed on its own thread. */
>> static void *app_function (void *userdata) {
>> 
>> // .....
>> 
>>  /* Build pipeline */
>>  const gchar * part1 = "tcpclientsrc host=";
>>  gchar* pipeline_definition;
>>  pipeline_definition = malloc(109); //Number of characters in the pipeline
>> definition
>>  strcpy(pipeline_definition, part1); // copy the part 1 into the new var
>>  strcat(pipeline_definition, serverIpAddress); // add the ip address
>>  const gchar *  part2 = " port=5000 ! gdpdepay ! rtph264depay ! ffdec_h264
>> ! autovideosink sync=false";
>>  strcat(pipeline_definition, part2);
>> 
>>  data->pipeline = gst_parse_launch(pipeline_definition, &error);
> 
> May I suggest something like:
> 
>   pipeline_definition =
>       g_strdup_printf ("tcpclientsrc host=%s port=5000 "
>           " ! gdpdepay ! rtph264depay ! ffdec_h264 "
>           "! autovideosink sync=false", serverIpAddress);
> 
>   data->pipeline = gst_parse_launch (pipeline_definition, &error)
> 
>   g_free (pipeline_definition);
> 
> But in any case, it seems like the problem is the construction of your
> pipeline string. My guess would be that serverIpAddress never gets set
> to anything, OR you're setting it to a string that's only valid for a
> very short time inside .._nativeSetIpserver(), and you're strcat()ing
> garbage or a now-freed string into the pipeline_definition string.
> Should be easy to verify with a few printf in strategic places.
> 
>> JNIEXPORT void JNICALL
>> Java_com_gst_sdk_tutorials_tutorial_3_Tutorial3_nativeSetIpserver(JNIEnv *
>> env, jobject obj, jstring ipAddress)
>> {
>>        const char *temp = (*env)->GetStringUTFChars(env, ipAddress, 0);
>>        serverIpAddress = temp;
>>        (*env)->ReleaseStringUTFChars(env, ipAddress, temp);
> 
> Is this function getting called?
> 
> Does   serverIpAddress = g_strdup (temp);   help?
> 
> Cheers
> -Tim
> 
> -- 
> Tim Müller, Centricular Ltd - http://www.centricular.com
> 
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Chris Tapp

opensource at keylevel.com
www.keylevel.com