ffmpeg Video Scan Progress during Frame Extarction

5
votes

I scan input video to extract certain frames using ffmpeg's select filter. The selection is based on a complex creteria and the number of extracted frames can't be predicted (I'm doing scene detection, but this can be something different - e.g. selecting all the I frames, etc).

What I need is to display the percentage of scanned (decoded) video (e.g. 10% or 90%).

I tried several ways to do this parsing console output as people usually do when dealing with encoding, but it doesn't help with the progress of scanning (e.g. Can ffmpeg show a progress bar? or ffmpeg Progress Bar - Encoding Percentage in PHP)

ffmpeg -progress sceneProgr.txt -i input.wmv -vsync passthrough -an -vf select='gt(scene\,0.2)',showinfo scene%%05d.png

The output this produces is as follows:

<..>    
frame=    0 fps=0.0 q=0.0 size=N/A time=00:00:00.00 bitrate=N/A    
n:0 pts:16550 pts_time:16.55 pos:4205325 fmt:rgb24 sar:0/1 s:640x480 i:P iskey:1 type:I checksum:95895BC9 plane_checksum:[95895BC9]
frame=    1 fps=0.7 q=0.0 size=N/A time=00:00:00.00 bitrate=N/A    
n:1 pts:24591 pts_time:24.591 pos:6685325 fmt:rgb24 sar:0/1 s:640x480 i:P iskey:0 type:P checksum:FF4CC015 plane_checksum:[FF4CC015]
'frame=...' and 'n:...' lines are repeated for each of the extracted frames.

Both frame=... and n:... lines refer to the numbers in the output and therefore can't be used to calculate progress the way people usually do this (as I can't predict how many frames will be found beforehead and besides, they are not uniformly spread across the input video).

If I specify -progress progress.txt parameter, the progress.txt file is as follows:

frame=5
fps=1.2
stream_0_0_q=0.0
total_size=N/A
out_time_ms=43209833
out_time=00:00:43.209833
dup_frames=0
drop_frames=0
progress=continue


frame=6
fps=1.3
stream_0_0_q=0.0
total_size=N/A
out_time_ms=52252200
out_time=00:00:52.252200
dup_frames=0
drop_frames=0
progress=continue

frame=6
fps=1.2
stream_0_0_q=0.0
total_size=N/A
out_time_ms=52252200
out_time=00:00:52.252200
dup_frames=0
drop_frames=0
progress=continue

New portion is written approximately every second and refers to the last extracted frame. Which is somewhat helpful as out_time refers to the last extracted frames' position in the input video, so I can calculate the progress of the scan from it as 

progress = out_time_ms/total_input_time

But this is not ideal as it will be updated only when the new frame which matches the select criteria is extracted. So, If I have a large portion of video with no matching frames, the progress won't change for a lot of time.

Wrapping-up:

I am looking for a way to calculate the progress of video scanning when using select filter.

Any ideas are strongly appreciated.

1
videoffmpegprogressffprobe
try using stats that report what has NOT been process yet to get at percent complete. each frame has a timestamp. on init , you have var for total duration. those 2 vars always provide measure of progress - Robert Rowntree
@RobertRowntree , thanks for taking a look: how do I get this "tats that report what has NOT been process yet" which you refer to? - Isantipov
the stdout info on ffmpeg for input media tracks at BEGIN includes 'duration' or the total length in seconds.... can you READ this or get it somehow? Then , use that along with the timestamp on every frame to figure out percent complete . - Robert Rowntree
@RobertRowntree , I can get the total length easily, my problem is that I can't get the currently decoded/scanned frame number as ffmpeg outputs the frame stat only if it has passed through the select condition (see the first example output in my question). - Isantipov

1 Answers

0
votes

what you get on every frame like data from ffprobe.....

[FRAME]
media_type=video
key_frame=1
pkt_pts=0
pkt_pts_time=0.000000
pkt_dts=0
pkt_dts_time=0.000000
pkt_duration=1
pkt_duration_time=0.040000
pkt_pos=44
width=800
height=542
pix_fmt=yuv420p
sample_aspect_ratio=1:1
pict_type=I
coded_picture_number=0
display_picture_number=0
interlaced_frame=0
top_field_first=0
repeat_pict=0
reference=3
[/FRAME]

what you get at BEGIN

I/stderr  ( 7434): Input #0, image2, from '/storage/sdcard0/Pictures/me374658335.jpg':
I/stderr  ( 7434):   Duration: 00:00:00.04, start: 0.000000, bitrate: N/A
I/stderr  ( 7434):     Stream #0:0: Video: mjpeg, yuvj420p, 1296x972 [SAR 1:1 DAR 4:3], 25 fps, 25 tbr, 25 tbn, 25 tbc
I/stderr  ( 7434): Input #1, mov,mp4,m4a,3gp,3g2,mj2, from '/storage/sdcard0/PictureComment/1347139284144.3gp':
I/stderr  ( 7434):   Metadata:
I/stderr  ( 7434):     major_brand     : 3gp4
I/stderr  ( 7434):     minor_version   : 0
I/stderr  ( 7434):     compatible_brands: isom3gp4
I/stderr  ( 7434):     creation_time   : 2012-09-08 21:21:41
I/stderr  ( 7434):   Duration: 00:00:17.22, start: 0.000000, bitrate: 67 kb/s
I/stderr  ( 7434):     Stream #1:0(eng): Audio: aac (mp4a / 0x6134706D), 44100 Hz, mono, s16, 64 kb/s
I/stderr  ( 7434):     Metadata:
I/stderr  ( 7434):       creation_time   : 2012-09-08 21:21:41
I/stderr  ( 7434):       handler_name    : SoundHandle
I/stderr  ( 7434): [libx264 @ 0x5a070910] using SAR=1/1
I/stderr  ( 7434): [libx264 @ 0x5a070910] using cpu capabilities: ARMv6 NEON
I/stderr  ( 7434): [libx264 @ 0x5a070910] profile High, level 3.2

can you use the frame timestamp along with the Duration to calculate percent complete?