Enable reading srts from a pipe

examples/flv+srt.c

@@ -21,38 +21,86 @@
 /* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN                  */
 /* THE SOFTWARE.                                                                              */
 /**********************************************************************************************/
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
 #include "srt.h"
 #include "flv.h"
 #include "avc.h"
-// #include "sei.h"
 
-#define MAX_SRT_SIZE (10*1024*1024)
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#define MAX_SRT_SIZE (1*1024*1024)
 
-// TODO replace this with utf8_load_text_file
-srt_t* srt_from_file (const char* path)
+// retunes number of bytes read
+// negative number on error
+// retursn 0 on 'not ready' and 'eof'
+// eof set to 1 on end, otherwise zero
+size_t fd_read (int fd, uint8_t* data, size_t size, int* eof)
 {
-    srt_t* head = 0;
+    fd_set rfds;
+    struct timeval tv;
+    int retval;
+
+    (*eof) = 0;
+    FD_ZERO (&rfds);
+    FD_SET (fd, &rfds);
+    tv.tv_sec = 0;
+    tv.tv_usec = 1;
+    retval = select (fd+1, &rfds, NULL, NULL, &tv);
+
+    if (0 > retval) {
+        return retval;
+    }
+
+    // not ready
+    if (! (retval && FD_ISSET (fd, &rfds))) {
+        return 0;
+    }
 
-    size_t srt_size = 0;
-    utf8_char_t* srt_data = utf8_load_text_file (path, &srt_size);
+    retval = read (fd,data,size);
 
-    if (srt_size&&srt_data) {
-        head = srt_parse (srt_data,srt_size);
-        free (srt_data);
+    if (0 == retval) {
+        (*eof) = 1;
     }
 
-    return head;
+    return retval;
+}
+
+size_t g_srt_size = 0;
+utf8_char_t g_srt_data[MAX_SRT_SIZE];
+srt_t* srt_from_fd (int fd)
+{
+    char c;
+    int eof;
+
+    for (;;) {
+        int ret = fd_read (fd,&c,1,&eof);
+
+        if (eof || (1 == ret && 0 == c)) {
+            srt_t* srt = srt_parse (&g_srt_data[0],g_srt_size);
+            g_srt_size = 0;
+            return srt;
+        }
+
+        if (1 == ret) {
+            g_srt_data[g_srt_size] = c;
+            g_srt_size += 1;
+        } else {
+            return 0;
+        }
+    }
 }
 
 int main (int argc, char** argv)
 {
     flvtag_t tag;
-    double timestamp, clear_timestamp = 0;
+    srt_t* old_srt, *nxt_srt = 0;
+    double timestamp, offset, clear_timestamp = 0;
     int has_audio, has_video;
     FILE* flv = flv_open_read (argv[1]);
+    int fd = open (argv[2],O_RDWR);
     FILE* out = flv_open_write (argv[3]);
 
     flvtag_init (&tag);
@@ -62,27 +110,31 @@ int main (int argc, char** argv)
         return EXIT_FAILURE;
     }
 
-    srt_t* head = srt_from_file (argv[2]);
-    srt_t* srt = head;
-
-    if (! head) {
-        fprintf (stderr,"%s is not an srt file\n", argv[2]);
-        return EXIT_FAILURE;
-    }
-
     flv_write_header (out,has_audio,has_video);
 
+    fprintf (stderr, "Reading flv from %s\n", argv[1]);
+    fprintf (stderr, "Reading captons from %s\n", argv[2]);
+    fprintf (stderr, "Writing flv to %s\n", argv[3]);
+
     while (flv_read_tag (flv,&tag)) {
-        // TODO handle B frames better
 
-        if (flvtag_avcpackettype_nalu == flvtag_avcpackettype (&tag)) {
-            timestamp = flvtag_pts_seconds (&tag);
+        srt_t* new_srt = srt_from_fd (fd);
+        timestamp = flvtag_pts_seconds (&tag);
 
-            if (srt && srt->timestamp <= timestamp) {
-                fprintf (stderr,"T: %0.02f (%0.02fs):\n%s\n", srt->timestamp, srt->duration, srt_data (srt));
-                clear_timestamp = srt->timestamp + srt->duration;
-                flvtag_addcaption_text (&tag, srt_data (srt));
-                srt = srt->next;
+        if (new_srt) {
+            fprintf (stderr,"Loaded new SRT at time %f\n",timestamp);
+            srt_free (old_srt);
+            old_srt = new_srt;
+            nxt_srt = new_srt;
+            offset = timestamp;
+        }
+
+        if (flvtag_avcpackettype_nalu == flvtag_avcpackettype (&tag)) {
+            if (nxt_srt && (offset+nxt_srt->timestamp) <= timestamp) {
+                fprintf (stderr,"T: %0.02f (%0.02fs):\n%s\n", (offset+nxt_srt->timestamp), nxt_srt->duration, srt_data (nxt_srt));
+                clear_timestamp = (offset+nxt_srt->timestamp) + nxt_srt->duration;
+                flvtag_addcaption_text (&tag, srt_data (nxt_srt));
+                nxt_srt = nxt_srt->next;
             } else if (0 <= clear_timestamp && clear_timestamp <= timestamp) {
                 fprintf (stderr, "T: %0.02f: [CAPTIONS CLEARED]\n", timestamp);
                 flvtag_addcaption_text (&tag, NULL);
@@ -93,7 +145,7 @@ int main (int argc, char** argv)
         flv_write_tag (out,&tag);
     }
 
-    srt_free (head);
+    srt_free (old_srt);
     flvtag_free (&tag);
     flv_close (flv);
     flv_close (out);

src/srt.c

@@ -83,6 +83,10 @@ srt_t* srt_parse (const utf8_char_t* data, size_t size)
     size_t line_length = 0, trimmed_length = 0;
     int hh1, hh2, mm1, mm2, ss1, ss2, ms1, ms2;
 
+    if (!data||!size) {
+        return 0;
+    }
+
     for (;;) {
         line_length = 0;