[FFmpeg-devel] [PATCH] What is missing for working AVFMT_FLAG_NONBLOCK?

[Michael Niedermayer]

On Tue, Mar 03, 2009 at 03:06:21AM +0100, Michael Niedermayer wrote:
> Hi
> 
> AVFMT_FLAG_NONBLOCK is not enabled in ffmpeg/ffplay.c
> what is missing for it?
> capturing from several devices is likely going to work better if they
> dont block. And yes i know it all should be using select() but that is
> harder. And simple polling with non blocking demuxers should already
> work pretty well.
> 
> is the only thing missing the code in ffmpeg.c that picks files
> based on the next expected timestamp?
> 
> id like to set AVFMT_FLAG_NONBLOCK by default in ffmpeg.c

The patch that i had in mind is below, passes reg tests

comments welcome (if i receive none or no  objections than ill apply
tomorrow)

Index: ffmpeg.c
===================================================================
--- ffmpeg.c	(revision 17740)
+++ ffmpeg.c	(working copy)
@@ -1559,6 +1559,8 @@
     AVInputFile *file_table;
     int key;
     int want_sdp = 1;
+    uint8_t no_packet[MAX_FILES]={0};
+    int no_packet_count=0;
 
     file_table= av_mallocz(nb_input_files * sizeof(AVInputFile));
     if (!file_table)
@@ -2067,6 +2069,8 @@
             ost = ost_table[i];
             os = output_files[ost->file_index];
             ist = ist_table[ost->source_index];
+            if(no_packet[ist->file_index])
+                continue;
             if(ost->st->codec->codec_type == CODEC_TYPE_VIDEO)
                 opts = ost->sync_opts * av_q2d(ost->st->codec->time_base);
             else
@@ -2089,6 +2093,11 @@
         }
         /* if none, if is finished */
         if (file_index < 0) {
+            if(no_packet_count){
+                no_packet_count=0;
+                memset(no_packet, 0, sizeof(no_packet));
+                continue;
+            }
             break;
         }
 
@@ -2103,8 +2112,11 @@
         /* read a frame from it and output it in the fifo */
         is = input_files[file_index];
         ret= av_read_frame(is, &pkt);
-        if(ret == AVERROR(EAGAIN) && strcmp(is->iformat->name, "ffm"))
+        if(ret == AVERROR(EAGAIN) && strcmp(is->iformat->name, "ffm")){
+            no_packet[file_index]=1;
+            no_packet_count++;
             continue;
+        }
         if (ret < 0) {
             file_table[file_index].eof_reached = 1;
             if (opt_shortest)
@@ -2113,6 +2125,9 @@
                 continue;
         }
 
+        no_packet_count=0;
+        memset(no_packet, 0, sizeof(no_packet));
+
         if (do_pkt_dump) {
             av_pkt_dump_log(NULL, AV_LOG_DEBUG, &pkt, do_hex_dump);
         }
@@ -3412,6 +3427,7 @@
     oc->preload= (int)(mux_preload*AV_TIME_BASE);
     oc->max_delay= (int)(mux_max_delay*AV_TIME_BASE);
     oc->loop_output = loop_output;
+    oc->flags |= AVFMT_FLAG_NONBLOCK;
 
     set_context_opts(oc, avformat_opts, AV_OPT_FLAG_ENCODING_PARAM);
 

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Thouse who are best at talking, realize last or never when they are wrong.
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