<div dir="ltr"><div> </div><div>Thank you Sebastian!!</div><div> </div><div>I can now access the subtitle stream that is closely sync'ed up with the video. I am using appsink as suggested on the playbin2 text-sink property to pull the text buffer and computing the running time using base time and clock. </div> <div> </div><div>One issue that I now have is that subtitle is not displayed on the final video. Is this because of using appsink on the text-sink property instead of an actual text processing element. Any idea how I can fix this - get the subtitle text and timestamp in my console output and also display the same on the final video.</div> <div> </div><div>Gracias</div><div>Dece</div> <div class="gmail_extra"><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"> ---------------------------------------------------------------------- Message: 1 Date: Tue, 12 Nov 2013 07:36:18 -0500 From: Dece Bel <<a href="mailto:decebel@gmail.com">decebel@gmail.com</a>> To: <a href="mailto:gstreamer-devel@lists.freedesktop.org">gstreamer-devel@lists.freedesktop.org</a> Subject: buffer probe data out of sync for subtitle text pad Message-ID: <CAPqbHrgBUaeE9KLzA=<a href="mailto:ib_dc-5pDayLJ20wOxazSSH7Xs6XJJbA@mail.gmail.com">ib_dc-5pDayLJ20wOxazSSH7Xs6XJJbA@mail.gmail.com</a>> Content-Type: text/plain; charset="iso-8859-1" I am trying to read subtitle from a video and want to record the timestamp of the subtitled text in the gstreamer pipeline. One approach that I have been trying is with the getting the action signal on playbin for "get-text-pad" and attaching a probe on the pad. Eventually when the callback (cb_have_data) is called, I do see the text in the buffer dumped on console. However, I notice that the subtitle on the final rendered video and the one dumped from the probe callback are out of sync. Can someone pls suggest how to get the timestamp of the subtitled text from the stream or received a sync'ed stream or any other approach. Gracias Dece below is some relevant stripped code that uses the playbin element (using gstreamer 1.0) main() { // creating the playbin element and setting flags to also play sub-titles ... ... .. ... g_signal_emit_by_name (data->playbin, "get-text-pad", 0, &txt_pad); if(txt_pad) { printf("\nwe have a text pad"); *c**a_pad_data(txt_pad);* } } /////////////////////////////////////// // When text pad is added, the below function will attach a probe *void cb_pad_added(GstPad* pd) {* * gchar *name;* * GstCaps *caps = NULL;* * name = gst_pad_get_name (pd);* * g_print ("\nA new pad %s was created\n", name);* * g_free (name);* * gst_pad_add_probe (pd, GST_PAD_PROBE_TYPE_BUFFER, (GstPadProbeCallback) cb_have_data, NULL, NULL);* * gst_object_unref (pd);* *}* /////////////////////////////////////////////// // probe call back. Read the buffer an size and then print the buffer text to screen. *static GstPadProbeReturn* *cb_have_data (GstPad *pad,* * GstPadProbeInfo *info,* * gpointer user_data) {* * GstBuffer *buffer;* * char text_msg[128];* * gint sz, sz2;* * memset(text_msg, 0, sizeof(text_msg));* * buffer = GST_PAD_PROBE_INFO_BUFFER (info);* * sz = gst_buffer_get_size(buffer);* * sz2 = gst_buffer_extract(buffer, 0, text_msg, sz);* * g_print ("\nBuffer Size is %d, read %d, data: %s", sz, sz2, text_msg);* * return GST_PAD_PROBE_OK;* *}* -------------- next part -------------- An HTML attachment was scrubbed... URL: <<a href="http://lists.freedesktop.org/archives/gstreamer-devel/attachments/20131112/9268a936/attachment-0001.html" target="_blank">http://lists.freedesktop.org/archives/gstreamer-devel/attachments/20131112/9268a936/attachment-0001.html</a>> ------------------------------ Message: 2 Date: Tue, 12 Nov 2013 13:44:36 +0100 From: Sebastian Dr?ge <<a href="mailto:sebastian@centricular.com">sebastian@centricular.com</a>> To: Discussion of the development of and with GStreamer <<a href="mailto:gstreamer-devel@lists.freedesktop.org">gstreamer-devel@lists.freedesktop.org</a>> Subject: Re: buffer probe data out of sync for subtitle text pad Message-ID: <1384260276.2586.6.camel@thor.lan> Content-Type: text/plain; charset="utf-8" On Di, 2013-11-12 at 07:36 -0500, Dece Bel wrote: > I am trying to read subtitle from a video and want to record the timestamp > of the subtitled text in the gstreamer pipeline. > One approach that I have been trying is with the getting the action signal > on playbin for "get-text-pad" > and attaching a probe on the pad. Eventually when the callback > (cb_have_data) is called, I do see the text in the buffer dumped on console. > > However, I notice that the subtitle on the final rendered video and the one > dumped from the probe callback are out of sync. > Can someone pls suggest how to get the timestamp of the subtitled text from > the stream or received a sync'ed stream or any other approach. You could also set a text-sink on playbin btw. But the problem stays the same wrt synchronization. You need to convert the buffer timestamps to running-time, and then check them against the current running time of the sink (clock_time - base_time). Usually you will get buffers much earlier and then need to wait a bit until they are to be displayed. -- Sebastian Dr?ge <<a href="mailto:sebastian@centricular.com">sebastian@centricular.com</a>> Centricular Ltd - <a href="http://www.centricular.com" target="_blank">http://www.centricular.com</a> Expertise, Straight from the Source -------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 966 bytes Desc: This is a digitally signed message part URL: <<a href="http://lists.freedesktop.org/archives/gstreamer-devel/attachments/20131112/f7043ba5/attachment-0001.pgp" target="_blank">http://lists.freedesktop.org/archives/gstreamer-devel/attachments/20131112/f7043ba5/attachment-0001.pgp</a>> </blockquote></div></div></div>