[FFmpeg-devel] [PATCH 10/29] fftools/ffmpeg: factorize checking whether any output was written

[Anton Khirnov]

This is currently done in two places:
* at the end of print_final_stats(), which merely prints a warning if
  the total size of all written packets is zero
* at the end of transcode() (under a misleading historical 'close each
  encoder' comment), which instead checks the packet count to implement
  -abort_on empty_output[_stream]

Consolidate both of these blocks into a single function called from
of_write_trailer(), which is a more appropriate place for this. Also,
return an error code rather than exit immediately, which ensures all
output files are properly closed.
---
 fftools/ffmpeg.c     | 30 ------------------------------
 fftools/ffmpeg_mux.c | 43 +++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 43 insertions(+), 30 deletions(-)

diff --git a/fftools/ffmpeg.c b/fftools/ffmpeg.c
index 7431482acc..48e771cbc5 100644
--- a/fftools/ffmpeg.c
+++ b/fftools/ffmpeg.c
@@ -745,7 +745,6 @@ static void print_final_stats(int64_t total_size)
     uint64_t data_size = 0;
     float percent = -1.0;
     int i, j;
-    int pass1_used = 1;
 
     for (OutputStream *ost = ost_iter(NULL); ost; ost = ost_iter(ost)) {
         AVCodecParameters *par = ost->st->codecpar;
@@ -759,10 +758,6 @@ static void print_final_stats(int64_t total_size)
         }
         extra_size += par->extradata_size;
         data_size  += s;
-        if (ost->enc_ctx &&
-            (ost->enc_ctx->flags & (AV_CODEC_FLAG_PASS1 | AV_CODEC_FLAG_PASS2))
-            != AV_CODEC_FLAG_PASS1)
-            pass1_used = 0;
     }
 
     if (data_size && total_size>0 && total_size >= data_size)
@@ -848,14 +843,6 @@ static void print_final_stats(int64_t total_size)
         av_log(NULL, AV_LOG_VERBOSE, "  Total: %"PRIu64" packets (%"PRIu64" bytes) muxed\n",
                total_packets, total_size);
     }
-    if(video_size + data_size + audio_size + subtitle_size + extra_size == 0){
-        av_log(NULL, AV_LOG_WARNING, "Output file is empty, nothing was encoded ");
-        if (pass1_used) {
-            av_log(NULL, AV_LOG_WARNING, "\n");
-        } else {
-            av_log(NULL, AV_LOG_WARNING, "(check -ss / -t / -frames parameters if used)\n");
-        }
-    }
 }
 
 static void print_report(int is_last_report, int64_t timer_start, int64_t cur_time)
@@ -2902,7 +2889,6 @@ static int transcode(void)
     int ret, i;
     InputStream *ist;
     int64_t timer_start;
-    int64_t total_packets_written = 0;
 
     ret = transcode_init();
     if (ret < 0)
@@ -2957,22 +2943,6 @@ static int transcode(void)
     /* dump report by using the first video and audio streams */
     print_report(1, timer_start, av_gettime_relative());
 
-    /* close each encoder */
-    for (OutputStream *ost = ost_iter(NULL); ost; ost = ost_iter(ost)) {
-        uint64_t packets_written;
-        packets_written = atomic_load(&ost->packets_written);
-        total_packets_written += packets_written;
-        if (!packets_written && (abort_on_flags & ABORT_ON_FLAG_EMPTY_OUTPUT_STREAM)) {
-            av_log(ost, AV_LOG_FATAL, "Empty output\n");
-            exit_program(1);
-        }
-    }
-
-    if (!total_packets_written && (abort_on_flags & ABORT_ON_FLAG_EMPTY_OUTPUT)) {
-        av_log(NULL, AV_LOG_FATAL, "Empty output\n");
-        exit_program(1);
-    }
-
     return ret;
 }
 
diff --git a/fftools/ffmpeg_mux.c b/fftools/ffmpeg_mux.c
index c2b7993e66..9a91861bd4 100644
--- a/fftools/ffmpeg_mux.c
+++ b/fftools/ffmpeg_mux.c
@@ -598,6 +598,45 @@ int of_stream_init(OutputFile *of, OutputStream *ost)
     return mux_check_init(mux);
 }
 
+static int check_written(OutputFile *of)
+{
+    int64_t total_packets_written = 0;
+    int pass1_used = 1;
+    int ret = 0;
+
+    for (int i = 0; i < of->nb_streams; i++) {
+        OutputStream *ost = of->streams[i];
+        uint64_t packets_written = atomic_load(&ost->packets_written);
+
+        total_packets_written += packets_written;
+
+        if (ost->enc_ctx &&
+            (ost->enc_ctx->flags & (AV_CODEC_FLAG_PASS1 | AV_CODEC_FLAG_PASS2))
+             != AV_CODEC_FLAG_PASS1)
+            pass1_used = 0;
+
+        if (!packets_written &&
+            (abort_on_flags & ABORT_ON_FLAG_EMPTY_OUTPUT_STREAM)) {
+            av_log(ost, AV_LOG_FATAL, "Empty output stream\n");
+            ret = err_merge(ret, AVERROR(EINVAL));
+        }
+    }
+
+    if (!total_packets_written) {
+        int level = AV_LOG_WARNING;
+
+        if (abort_on_flags & ABORT_ON_FLAG_EMPTY_OUTPUT) {
+            ret = err_merge(ret, AVERROR(EINVAL));
+            level = AV_LOG_FATAL;
+        }
+
+        av_log(of, level, "Output file is empty, nothing was encoded%s\n",
+               pass1_used ? "" : "(check -ss / -t / -frames parameters if used)");
+    }
+
+    return ret;
+}
+
 int of_write_trailer(OutputFile *of)
 {
     Muxer *mux = mux_from_of(of);
@@ -629,6 +668,10 @@ int of_write_trailer(OutputFile *of)
         }
     }
 
+    // check whether anything was actually written
+    ret = check_written(of);
+    mux_result = err_merge(mux_result, ret);
+
     return mux_result;
 }
 
-- 
2.39.1