CODEWITHSUNDEEP
ffmpeg
ethrbunny
ethrbunny

Reputation: 10469

FFMPEG - errors when combining videos

I have two .OGG files of similar size, FPS and duration. My goal is to combine them into a side-by-side presentation using FFMPEG. To this end I've tried the following cmd:

ffmpeg -i subject.ogg -vf "[in]pad=3*iw:3*ih[left];movie=clinician.ogg[right];[left] [right]overlay=100:0[out]" combined.ogg

Suffice to say that the resultant video is non-playable. During the combination process FFMPEG prints lots of errors that read like:

[Parsed_overlay_2 @ 0x1eb7d3e0] Buffer queue overflow, dropping

What is this telling me?

Note:

So - what's wrong with my parameters and what am I doing to cause these FFMPEG errors?

EDIT:
ffmpeg -i clinician.ogg

Input #0, ogg, from 'clinician.ogg':
Duration: 00:05:20.98, start: 0.001000, bitrate: 2273 kb/s
Stream #0:0: Video: theora, yuv420p, 500x500 [SAR 1:1 DAR 1:1], 1k tbr, 1k tbn, 1k tbc
Metadata:
SERVER : Red5 Server 1.0.0 RC1 $Rev: 4193 $
CANSEEKTOEND : true
ENCODER : Lavf54.31.100
Stream #0:1: Audio: vorbis, 8000 Hz, stereo, s16
Metadata:
SERVER : Red5 Server 1.0.0 RC1 $Rev: 4193 $
CANSEEKTOEND : true
ENCODER : Lavf54.31.100

ffmpeg -i subject.ogg

Input #0, ogg, from 'subject.ogg':
Duration: 00:05:17.60, start: 0.001000, bitrate: 1341 kb/s
Stream #0:0: Video: theora, yuv420p, 300x300 [SAR 1:1 DAR 1:1], 83.33 tbr, 1k tbn, 1k tbc
Metadata:
SERVER : Red5 Server 1.0.0 RC1 $Rev: 4193 $
CANSEEKTOEND : true
ENCODER : Lavf54.31.100
Stream #0:1: Audio: vorbis, 8000 Hz, stereo, s16
Metadata:
SERVER : Red5 Server 1.0.0 RC1 $Rev: 4193 $
CANSEEKTOEND : true
ENCODER : Lavf54.31.100

Upvotes: 3

Views: 3945

Answers (2)

Alex I
Alex I

Reputation: 20287

It is probably easiest to do this using Avisynth.

Make the following input.avs file:

a = AviSource("first.avi")
b = AviSource("second.avi")
StackHorizontal(a,b)

Then run ffmpeg -i input.avs output.avi ... plus any other options you want.

EDIT: Another way to do it (not fast) is to dump the frames from both files to png and combine them with ImageMagick (for example montage) or similar image processing tools. 

#!/bin/bash
ffmpeg -i first.avi first_%05d.png
ffmpeg -i second.avi second_%05d.png
for file in first_*.png ; do montage ${file} ${file/first/second} ${file/first/output} ; done
ffmpeg -i output_%05d.png output.avi

This actually lets you do a lot more image processing than just side-by-side, you can do arbitrary scale/overlay/background/etc. The problem is that the N-th frame from one file may not be at exactly the same time as the N-th frame from the other file, if they are variable frame rate, this is something that AviSynth handles perfectly for you. If the clips are constant frame rate that is not a problem.

Combining clips by making a new clip containing both like this (whether through avisynth or not) requires recompressing the video, and reduces video quality/increases file size.

I am not sure how to read ogg files into Avisynth, but there is probably a way. Check the FAQ on input formats.

Side comment: The choice of theora/ogg is strange. Better: H.264 in mp4 container.

Upvotes: 0

ethrbunny
ethrbunny

Reputation: 10469

Converting to x264 was a great suggestion. That seemed to turn the tide.

Here are some notes for posterity:

  • to convert flv to x264 and correct audio sync issues:

ffmpeg -y -i subject_s_2242_r_1658.flv -async 1 -ac 2 -strict -2 -acodec vorbis \
-c:v libx264 -preset slow -crf 22 subject.mkv

  • to merge two x264 files into a single side-by-side file and put the two mono audio tracks into stereo in the resultant file:

ffmpeg -y -i clinician.mkv -vf: "movie=subject.mkv[right];pad=iw*2:ih:0:0[left];[left][right]overlay=500:0" \
-filter_complex "amovie=clinician.mkv[l];amovie=subject.mkv[r];[l][r] amerge" final.mkv

I was unable to install AVISYNTH (running on CentOS 6.2) but it does look like a great solution.

Upvotes: 2

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