Hello, I have no experience with submitting patches to ffmpeg yet and so I am
sorry if I am going about this the wrong way but I wanted to discuss a change
that I made to print_report which is related to this bug:
https://trac.ffmpeg.org/ticket/1446
We are using stdout from ffmpeg to monitor rtmp streams. Currently the FPS and
bitrate numbers which print_report outputs are calculated as a running average
- the total number of frames divided by the elapsed time and the total size in
bits divided by elapsed time.
This might make sense for files but for live streams it is not very useful
since over time the changes in the streams are reflected less and less.
My change is to output the actual frame rate and bit rate each time
print_report is called (every half a second or so). Also instead of using the
file size to calculate the bit rate, I use the sum of the data sizes written to
each stream which is giving me more consistent numbers..
Here is the diff, thank you for your feedback..
diff --git a/ffmpeg.c b/ffmpeg.c
index d3b8c4d..0c5afc9 100644
--- a/ffmpeg.c
+++ b/ffmpeg.c
@@ -1521,13 +1521,18 @@ static void print_report(int is_last_report, int64_t
timer_start, int64_t cur_ti
char buf[1024];
AVBPrint buf_script;
OutputStream *ost;
- AVFormatContext *oc;
- int64_t total_size;
+ int64_t total_size = 0;
AVCodecContext *enc;
int frame_number, vid, i;
- double bitrate;
+ double bitrate = -1;
int64_t pts = INT64_MIN + 1;
+ static int last_frame_number = 0;
static int64_t last_time = -1;
+ static int64_t last_frame_time = -1;
+ static int64_t last_file_size = 0;
+ static int64_t last_file_time = -1;
+ static float last_fps = -1;
+ static double last_bitrate = -1;
static int qp_histogram[52];
int hours, mins, secs, us;
@@ -1544,13 +1549,6 @@ static void print_report(int is_last_report, int64_t
timer_start, int64_t cur_ti
last_time = cur_time;
}
-
- oc = output_files[0]->ctx;
-
- total_size = avio_size(oc->pb);
- if (total_size <= 0) // FIXME improve avio_size() so it works with non
seekable output too
- total_size = avio_tell(oc->pb);
-
buf[0] = '\0';
vid = 0;
av_bprint_init(&buf_script, 0, 1);
@@ -1558,6 +1556,7 @@ static void print_report(int is_last_report, int64_t
timer_start, int64_t cur_ti
float q = -1;
ost = output_streams[i];
enc = ost->enc_ctx;
+ total_size += ost->data_size;
if (!ost->stream_copy)
q = ost->quality / (float) FF_QP2LAMBDA;
@@ -1567,16 +1566,20 @@ static void print_report(int is_last_report, int64_t
timer_start, int64_t cur_ti
ost->file_index, ost->index, q);
}
if (!vid && enc->codec_type == AVMEDIA_TYPE_VIDEO) {
- float fps, t = (cur_time-timer_start) / 1000000.0;
-
- frame_number = ost->frame_number;
- fps = t > 1 ? frame_number / t : 0;
+ int frame_number = ost->frame_number;
+ float frame_time_change = last_frame_time > 0 && cur_time >
last_frame_time ? (cur_time - last_frame_time) / 1000000.0 : 0;
+ float fps = frame_time_change > 0 ? (frame_number -
last_frame_number) / frame_time_change : 0;
+
snprintf(buf + strlen(buf), sizeof(buf) - strlen(buf), "frame=%5d
fps=%3.*f q=%3.1f ",
frame_number, fps < 9.95, fps, q);
av_bprintf(&buf_script, "frame=%d\n", frame_number);
av_bprintf(&buf_script, "fps=%.1f\n", fps);
av_bprintf(&buf_script, "stream_%d_%d_q=%.1f\n",
ost->file_index, ost->index, q);
+
+ last_frame_number = frame_number;
+ last_frame_time = cur_time;
+
if (is_last_report)
snprintf(buf + strlen(buf), sizeof(buf) - strlen(buf), "L");
if (qp_hist) {
@@ -1633,8 +1636,11 @@ static void print_report(int is_last_report, int64_t
timer_start, int64_t cur_ti
secs %= 60;
hours = mins / 60;
mins %= 60;
+
+ float file_time_change = (last_file_time >= 0 && cur_time >
last_file_time) ? (cur_time -last_file_time) / 1000000.0 : 0;
+ int64_t file_size_change = total_size > last_file_size ? total_size -
last_file_size : 0;
- bitrate = pts && total_size >= 0 ? total_size * 8 / (pts / 1000.0) : -1;
+ bitrate = file_time_change > 0 ? (file_size_change * 8) /
(file_time_change * 1000.0) : -1;
if (total_size < 0) snprintf(buf + strlen(buf), sizeof(buf) - strlen(buf),
"size=N/A time=");
@@ -1690,6 +1696,9 @@ static void print_report(int is_last_report, int64_t
timer_start, int64_t cur_ti
if (is_last_report)
print_final_stats(total_size);
+
+ last_file_time = cur_time;
+ last_file_size = total_size;
}
static void flush_encoders(void)
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