No Video
Ian Davidson
id012c3076 at blueyonder.co.uk
Mon Jan 7 01:17:54 PST 2013
Hi Kris,
You are correct when you say that you did not explain why my program
didn't work - but I tried your advice and now have 2 programs which
don't work.
I use a gst_parse_launch, passing it a string such as
"v4l2src norm=PAL ! videorate !
'video/x-raw,format=(string)I420,width=320,height=240,framerate=(fraction)25/1'
! queue ! mux. alsasrc ! audioconvert !
'audio/x-raw,rate=44100,channels=2' ! queue ! mux. avimux name=mux !
filesink location=file.avi"
but when I run the program I get a message
GStreamer-CRITICAL **: gst_element_make_from_uri: assertion
`gst_uri_is_valid (uri)' failed
I spent a good while chasing wild geese, asuming that the problem must
be with the file name I passed in for the filesink - but then studied
the debug trace more closely to see this extract
(SBCRecord2:2968): GStreamer-CRITICAL **: gst_element_make_from_uri:
assertion `gst_uri_is_valid (uri)' failed
0:00:00.172690420 [335m 2968[00m 0xc5f830 [31;01mERROR [00m
[00;01;37;41m GST_PIPELINE
./grammar.y:827:priv_gst_parse_yyparse:[00m no source element for
URI "/x-raw,rate=44100,channels=2'"
0:00:00.172703486 [335m 2968[00m 0xc5f830 [31;01mERROR [00m
[00;01;37;41m GST_PIPELINE
./grammar.y:744:priv_gst_parse_yyparse:[00m link without source element
0:00:00.172715265 [335m 2968[00m 0xc5f830 [31;01mERROR [00m
[00;01;37;41m GST_PIPELINE
./grammar.y:750:priv_gst_parse_yyparse:[00m link without sink element
(SBCRecord2:2968): GStreamer-CRITICAL **: gst_element_make_from_uri:
assertion `gst_uri_is_valid (uri)' failed
0:00:00.172740072 [335m 2968[00m 0xc5f830 [31;01mERROR [00m
[00;01;37;41m GST_PIPELINE
./grammar.y:827:priv_gst_parse_yyparse:[00m no source element for
URI
"/x-raw,format=(string)I420,width=320,height=240,framerate=(fraction)25/1'"
0:00:00.172753256 [335m 2968[00m 0xc5f830 [31;01mERROR [00m
[00;01;37;41m GST_PIPELINE
./grammar.y:744:priv_gst_parse_yyparse:[00m link without source element
0:00:00.172764467 [335m 2968[00m 0xc5f830 [31;01mERROR [00m
[00;01;37;41m GST_PIPELINE
./grammar.y:750:priv_gst_parse_yyparse:[00m link without sink element
For some reason, the caps I am passing in of "
'audio/x-raw,rate=44100,channels=2'" has been pulled apart and then
found to be broken. So copy-and-paste from a good command line into the
C program did not have 100% success.
Any help to get one (or both) versions of my program working would be
appreciated.
Ian
On 05/01/2013 22:36, Krzysztof Konopko wrote:
> Hi Ian,
>
> I don't know what particular problem in your app is, but in a situation
> when a pipeline works with gst-launch-1.0, but a C app doesn't, my stock
> advise is: copy your command line pipeline and use [1].
>
> You can start writing something dead simple and than introduce whatever
> complexity you need ensuring it still works at each step. In your
> particular case IMO you've introduced too much complexity.
>
> BTW, by using [1] your error checking reduces to something like this
> (pilfered/inspired from/by gst-launch.c):
>
> if (!pipeline) {
> g_printerr ("ERROR: pipeline could not be constructed: %s\n",
> error ? GST_STR_NULL (error->message) : "(unknown error)");
> goto untergang;
> } else if (error) {
> g_printerr ("Erroneous pipeline: %s\n", GST_STR_NULL (error->message));
> goto untergang;
> }
>
> [1]
> http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/gstreamer-GstParse.html#gst-parse-launch
>
> Kris
>
> On 05/01/13 17:06, Ian Davidson wrote:
>> If I use the following command, I can record Audio and Video into an AVI
>> File.
>>
>> gst-launch-1.0 -e v4l2src norm=PAL ! videorate !
>> 'video/x-raw,format=(string)I420,width=320,height=240,framerate=(fraction)25/1'
>> ! queue ! mux. alsasrc ! audioconvert !
>> 'audio/x-raw,rate=44100,channels=2' ! queue ! mux. avimux name=mux !
>> filesink location=script-test.avi
>>
>> I would like to replicate that in a program and my program is below.
>> However, the video does not make it through - the Audio plays OK when I
>> play the avi file.
>>
>> It had been suggested that videorate and audiorate might be beneficial
>> for me. In my program, if I included audiorate (as indicated by the
>> commented out lines), I just heard a brief burst of sound at the
>> beginning of the clip, whereas without audiorate, I heard the full
>> audio. Including/excluding videorate does not seem to make any
>> difference at the moment.
>>
>> I tried to set a value for "norm" on the v4l2src as PAL, but the
>> compiler did not recognise the ENUM value. The only way I could set it
>> was to use the value indicated by gst-inspect.
>>
>> I assume that I have done something stupid again, but I cannot see what
>> it is.
>>
>> Thanks for your help.
>>
>> Ian
>>
>> #include <gst/gst.h>
>> #include <glib.h>
>>
>>
>> static gboolean
>> bus_call (GstBus *bus,
>> GstMessage *msg,
>> gpointer data)
>> {
>> GMainLoop *loop = (GMainLoop *) data;
>>
>> switch (GST_MESSAGE_TYPE (msg)) {
>>
>> case GST_MESSAGE_EOS:
>> g_print ("End of stream\n");
>> g_main_loop_quit (loop);
>> break;
>>
>> case GST_MESSAGE_ERROR: {
>> gchar *debug;
>> GError *error;
>>
>> gst_message_parse_error (msg, &error, &debug);
>> g_free (debug);
>>
>> g_printerr ("Error: %s\n", error->message);
>> g_error_free (error);
>>
>> g_main_loop_quit (loop);
>> break;
>> }
>> default:
>> break;
>> }
>>
>> return TRUE;
>> }
>>
>>
>> static void
>> on_pad_added (GstElement *element,
>> GstPad *pad,
>> gpointer data)
>> {
>> GstPad *sinkpad;
>> GstElement *decoder = (GstElement *) data;
>>
>> /* We can now link this pad with the vorbis-decoder sink pad */
>> g_print ("Dynamic pad created, linking demuxer/decoder\n");
>>
>> sinkpad = gst_element_get_static_pad (decoder, "sink");
>>
>> gst_pad_link (pad, sinkpad);
>>
>> gst_object_unref (sinkpad);
>> }
>>
>>
>>
>> int
>> main (int argc,
>> char *argv[])
>> {
>> GMainLoop *loop;
>>
>> GstElement *pipeline, *vsource, *vcapsfilter, *vidrate, *queue1;
>> GstElement *asource, *aconv, *audrate, *acapsfilter, *queue2;
>> GstElement *mux, *sink;
>> GstBus *bus;
>> guint bus_watch_id;
>>
>> GstCaps *caps;
>>
>> /* Initialisation */
>> gst_init (&argc, &argv);
>>
>> loop = g_main_loop_new (NULL, FALSE);
>>
>>
>> /* Check input arguments */
>> if (argc != 2) {
>> g_printerr ("Usage: %s <AVI filename>\n", argv[0]);
>> return -1;
>> }
>>
>>
>> /* Create gstreamer elements */
>> pipeline = gst_pipeline_new ("av-recorder");
>> vsource = gst_element_factory_make ("v4l2src", "vid-source");
>> vcapsfilter = gst_element_factory_make ("capsfilter", "vid-caps");
>> vidrate = gst_element_factory_make ("videorate", "vidrate");
>> queue1 = gst_element_factory_make ("queue", "queue1");
>> asource = gst_element_factory_make ("alsasrc", "alsa-source");
>> aconv = gst_element_factory_make ("audioconvert", "audio-conv");
>> acapsfilter = gst_element_factory_make ("capsfilter", "audio-caps");
>> audrate = gst_element_factory_make ("audiorate", "audrate");
>> queue2 = gst_element_factory_make ("queue", "queue2");
>> mux = gst_element_factory_make ("avimux", "avi-mux");
>> sink = gst_element_factory_make ("filesink", "file-output");
>>
>> if (!pipeline || !vsource || !vcapsfilter || !vidrate || !queue1 ||
>> !asource || !aconv || !audrate || !acapsfilter || !queue2 || !mux ||
>> !sink) {
>> g_printerr ("One element could not be created. Exiting.\n");
>> return -1;
>> }
>>
>> /* Set up the pipeline */
>>
>> /* we set the output filename to the sink element */
>> g_object_set (G_OBJECT (sink), "location", argv[1], NULL);
>>
>> /* we set the video capabilities on the vidcaps element */
>> caps =
>> gst_caps_from_string("video/x-raw,format=(string)I420,width=320,height=240,framerate=(fraction)25/1");
>> g_object_set (G_OBJECT (vcapsfilter), "caps", caps, NULL);
>> gst_caps_unref (caps);
>>
>> /* we set the audio capabilities on the audiocaps element */
>> caps = gst_caps_from_string("audio/x-raw,rate=44100,channels=2");
>> g_object_set (G_OBJECT (acapsfilter), "caps", caps, NULL);
>> gst_caps_unref (caps);
>>
>> g_object_set (G_OBJECT (vsource), "norm", 255, NULL);
>>
>> /* we add a message handler */
>> bus = gst_pipeline_get_bus (GST_PIPELINE (pipeline));
>> bus_watch_id = gst_bus_add_watch (bus, bus_call, loop);
>> gst_object_unref (bus);
>>
>> /* we add all elements into the pipeline */
>> /* vsource, vcapsfilter, vidrate, queue1,
>> asource, aconv, acapsfilter, queue2,
>> mux, sink */
>> gst_bin_add_many (GST_BIN (pipeline),
>> vsource, vcapsfilter, queue1,
>> /* vsource, vidrate, vcapsfilter, queue1,*/
>> asource, aconv, acapsfilter, queue2,
>> /* asource, aconv, audrate, acapsfilter, queue2,*/
>> mux, sink, NULL);
>>
>> /* we link the elements together */
>> /* vsource -> vcapsfilter -> vidrate -> queue1 -> avimux
>> asource -> aconv -> acapsfilter -> queue2 -> avimux
>> mux -> sink */
>> gst_element_link_many (vsource, vcapsfilter, queue1, mux, NULL);
>> /* gst_element_link_many (vsource, vcapsfilter, vidrate, queue1, mux,
>> NULL);*/
>> gst_element_link_many (asource, aconv, acapsfilter, queue2, mux, NULL);
>> /* gst_element_link_many (asource, aconv, audrate, acapsfilter, queue2,
>> mux, NULL);*/
>> gst_element_link_many (mux, sink, NULL);
>>
>>
>> /* Set the pipeline to "playing" state*/
>> g_print ("Now recording: %s\n", argv[1]);
>> gst_element_set_state (pipeline, GST_STATE_PLAYING);
>>
>>
>> /* Iterate */
>> g_print ("Recording (or not!)...\n");
>> g_main_loop_run (loop);
>>
>>
>> /* Out of the main loop, clean up nicely */
>> g_print ("Returned, stopping recording\n");
>> gst_element_set_state (pipeline, GST_STATE_NULL);
>>
>> g_print ("Deleting pipeline\n");
>> gst_object_unref (GST_OBJECT (pipeline));
>> g_source_remove (bus_watch_id);
>> g_main_loop_unref (loop);
>>
>> return 0;
>> }
>> --
>> --
>> Ian Davidson
>> --
>>
--
--
Ian Davidson
--
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