ffmpeg: flush delayed frames in codec copy scenarios

Bitstream filters inserted between the input and output were never drained,
resulting in packets being lost if the bsf had any buffered.

Signed-off-by: James Almer <jamrial@gmail.com>

fftools/ffmpeg.c

@@ -2001,7 +2001,7 @@ static int check_output_constraints(InputStream *ist, OutputStream *ost)
     if (ost->source_index != ist_index)
         return 0;
 
-    if (ost->finished)
+    if (ost->finished & MUXER_FINISHED)
         return 0;
 
     if (of->start_time != AV_NOPTS_VALUE && ist->pts < of->start_time)
@@ -2733,7 +2733,9 @@ static int process_input_packet(InputStream *ist, const AVPacket *pkt, int no_eo
         }
         ist->pts = ist->dts;
         ist->next_pts = ist->next_dts;
-    }
+    } else if (!ist->decoding_needed)
+        eof_reached = 1;
+
     for (i = 0; i < nb_output_streams; i++) {
         OutputStream *ost = output_streams[i];
 
@@ -4213,11 +4215,12 @@ static int process_input(int file_index)
         for (i = 0; i < ifile->nb_streams; i++) {
             ist = input_streams[ifile->ist_index + i];
             avctx = ist->dec_ctx;
-            if (ist->decoding_needed) {
+            if (ist->processing_needed) {
                 ret = process_input_packet(ist, NULL, 1);
                 if (ret>0)
                     return 0;
-                avcodec_flush_buffers(avctx);
+                if (ist->decoding_needed)
+                    avcodec_flush_buffers(avctx);
             }
         }
 #if HAVE_THREADS
@@ -4247,7 +4250,7 @@ static int process_input(int file_index)
 
         for (i = 0; i < ifile->nb_streams; i++) {
             ist = input_streams[ifile->ist_index + i];
-            if (ist->decoding_needed) {
+            if (ist->processing_needed) {
                 ret = process_input_packet(ist, NULL, 0);
                 if (ret>0)
                     return 0;

fftools/ffmpeg.h

@@ -307,6 +307,7 @@ typedef struct InputStream {
     int decoding_needed;     /* non zero if the packets must be decoded in 'raw_fifo', see DECODING_FOR_* */
 #define DECODING_FOR_OST    1
 #define DECODING_FOR_FILTER 2
+    int processing_needed;   /* non zero if the packets must be processed */
 
     AVCodecContext *dec_ctx;
     const AVCodec *dec;

fftools/ffmpeg_filter.c

@@ -277,6 +277,7 @@ static void init_input_filter(FilterGraph *fg, AVFilterInOut *in)
 
     ist->discard         = 0;
     ist->decoding_needed |= DECODING_FOR_FILTER;
+    ist->processing_needed = 1;
     ist->st->discard = AVDISCARD_NONE;
 
     ifilter = ALLOC_ARRAY_ELEM(fg->inputs, fg->nb_inputs);

fftools/ffmpeg_opt.c

@@ -2610,6 +2610,7 @@ loop_end:
         if (ost->encoding_needed && ost->source_index >= 0) {
             InputStream *ist = input_streams[ost->source_index];
             ist->decoding_needed |= DECODING_FOR_OST;
+            ist->processing_needed = 1;
 
             if (ost->st->codecpar->codec_type == AVMEDIA_TYPE_VIDEO ||
                 ost->st->codecpar->codec_type == AVMEDIA_TYPE_AUDIO) {
@@ -2622,6 +2623,9 @@ loop_end:
                     exit_program(1);
                 }
             }
+        } else if (ost->stream_copy && ost->source_index >= 0) {
+            InputStream *ist = input_streams[ost->source_index];
+            ist->processing_needed = 1;
         }
 
         /* set the filter output constraints */