user19853: I have noticed today that when I use ffmpeg 4.0 stable to decode some TS files into y4m or ffv1 it occasionally skips some frames. My input file has all the frames burned into the picture and I am extracting some frames at regular intervals. Sometimes it works just fine without any skipped frames but sometimes it skips one or two frames. I am using the following command to decode my input:
ffmpeg -i input.ts -vsync 0 output.y4m

and I am extracting the frames using: 
ffmpeg -ss xxx -i output.y4m -vframes 1 xxx.png

I am substituting xxx with 0, 100, 200, etc and sometimes I see 1-2-3 frame dropped which is very annoying since I am trying to evaluate the PSNR afterwards and this is messing up the whole PSNR/SSIM evaluation. 
[EDIT] I have executed the command which @Gyan suggested:
ffmpeg -v 99 -loglevel 99 -i test.ts \
-c:v rawvideo -vsync 0 \
-enc_time_base 1/1000 output.nut &> test.log

And here is the log file test.log

user1871: Y4M has no timestamps, only framerate in its header. So, if your source has any variability in its framerate, you'll see a shift in apparent timestamp in the Y4M.
e.g.
n     src     y4m
0       0       0
1    0.04    0.04 
2    0.07    0.08
3    0.12    0.12
4    0.21    0.16
5    0.24    0.20
6    0.27    0.24 
...

Over a long period, these perturbations can add up. Here frame #6 in src is at TS of src #5 in Y4M.
Edit: the sample TS file has VFR timestamps.
Use -c:v rawvideo -vsync 0 -vf setpts=N/FRAME_RATE/TB -an and save to .nut.

19853: <p>I have noticed today that when I use ffmpeg 4.0 stable to decode some TS files into y4m or ffv1 it occasionally skips some frames. My input file has all the frames burned into the picture and I am extracting some frames at regular intervals. Sometimes it works just fine without any skipped frames but sometimes it skips one or two frames. I am using the following command to decode my input:</p>

<pre><code>ffmpeg -i input.ts -vsync 0 output.y4m
</code></pre>

<p>and I am extracting the frames using: </p>

<pre><code>ffmpeg -ss xxx -i output.y4m -vframes 1 xxx.png
</code></pre>

<p>I am substituting xxx with 0, 100, 200, etc and sometimes I see 1-2-3 frame dropped which is very annoying since I am trying to evaluate the PSNR afterwards and this is messing up the whole PSNR/SSIM evaluation. </p>

<p>[EDIT] I have executed the command which @Gyan suggested:</p>

<pre><code>ffmpeg -v 99 -loglevel 99 -i test.ts \
-c:v rawvideo -vsync 0 \
-enc_time_base 1/1000 output.nut &amp;&gt; test.log
</code></pre>

<p>And here is the log file <a href="https://we.tl/ePLv1JdfrT" rel="nofollow noreferrer">test.log</a></p>
 1871: <p>Y4M has no timestamps, only framerate in its header. So, if your source has any variability in its framerate, you'll see a shift in apparent timestamp in the Y4M.</p>

<p>e.g.</p>

<pre><code>n     src     y4m
0       0       0
1    0.04    0.04 
2    0.07    0.08
3    0.12    0.12
4    0.21    0.16
5    0.24    0.20
6    0.27    0.24 
...
</code></pre>

<p>Over a long period, these perturbations can add up. Here frame #6 in src is at TS of src #5 in Y4M.</p>

<p><strong>Edit</strong>: the sample TS file has VFR timestamps.</p>

<p>Use <code>-c:v rawvideo -vsync 0 -vf setpts=N/FRAME_RATE/TB -an</code> and save to <code>.nut</code>.</p>
