On 9/27/18 5:55 AM, DopeLabs wrote:
input: 90k tbn, 59.94 tbc
output: 30k tbn, 29.97 tbc
try explicitly specifying the output frame rate
-c:v h264 -r 29.97
On Sep 26, 2018, at 7:27 26PM, sean darcy <[email protected]> wrote:
I'm transcoding mpeg2 -> x264.
Stream #0:0[0x64]: Video: mpeg2video (Main) ([2][0][0][0] / 0x0002),
yuv420p(tv, progressive), 720x480 [SAR 8:9 DAR 4:3], Closed Captions, 29.97
fps, 59.94 tbr, 90k tbn, 59.94 tbc
When I run ffmpeg:
ffmpeg -i in.mpg -map 0:0 -map 0:2 -c:v libx264 -tune film -preset slow -crf 22
-c:a copy out.mp4
almost half the frames are dups:
frame=394550 fps=135 q=-1.0 Lsize= 2218652kB time=03:39:24.71
bitrate=1380.6kbits/s dup=175142 drop=0 speed=4.51x
Does this really mean that there were 175,142 frames with exact copies ? So
only ( 394,550 less 175,142 ) unique frames ?
The output looks fine. The input looks fine. What are these duplicated frames?
Is it an interlacing issue ? But the input is progressive.
Does it have to do with this warning:
[mp4 @ 0x921c80] track 1: codec frame size is not set
Output #0, mp4, to 'out.mp4':
Metadata:
encoder : Lavf58.18.103
Stream #0:0: Video: h264 (libx264) (avc1 / 0x31637661), yuv420p, 720x480
[SAR 8:9 DAR 4:3], q=-1--1, 29.97 fps, 30k tbn, 29.97 tbc
Metadata:
encoder : Lavc58.31.100 libx264
Puzzled.
But isn't that what ffmpeg does anyway:
ffprobe out.mp4
.........
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'out.mp4':
Metadata:
major_brand : isom
minor_version : 512
compatible_brands: isomiso2avc1mp41
encoder : Lavf58.18.103
Duration: 00:21:40.97, start: 0.000000, bitrate: 1346 kb/s
Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p,
720x480 [SAR 8:9 DAR 4:3], 944 kb/s, 29.97 fps, 29.97 tbr, 30k tbn,
59.94 tbc (default)
Metadata:
handler_name : VideoHandler
Does specifying the frame rate do anything but silence the dup warnings
? I mean, does ffmpeg do anything different when it's transcoding ?
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