[libav-tools] Converting video format when audio is out of sync
derrell.lipman at unwireduniverse.com
Wed Apr 22 15:43:01 CEST 2015
Thanks, Sampsa. It's telling me that the -filter_complex option doesn't
exist. I thought maybe the underscore was supposed to be a space, and
"complex" was the filter name, but there's no filter called "complex".
(I've attached the output of avconv -filters at the end of this message.)
My video isn't just slightly out of sync, though, as it sounds like you're
imagining. There's no relationship between the sound and the video; they're
no where near each other, when played with anything other than avplay.
Output of avconv -filters for my version of avconv:
anull Pass the source unchanged to the output.
anullsrc Null audio source, never return audio frames.
anullsink Do absolutely nothing with the input audio.
copy Copy the input video unchanged to the output.
crop Crop the input video to width:height:x:y.
drawbox Draw a colored box on the input video.
fade Fade in/out input video
fieldorder Set the field order.
fifo Buffer input images and send them when they are requested.
format Convert the input video to one of the specified pixel
gradfun Debands video quickly using gradients.
hflip Horizontally flip the input video.
lut Compute and apply a lookup table to the RGB/YUV input
lutrgb Compute and apply a lookup table to the RGB input video.
lutyuv Compute and apply a lookup table to the YUV input video.
negate Negate input video.
noformat Force libavfilter not to use any of the specified pixel
formats for the input to the next filter.
null Pass the source unchanged to the output.
overlay Overlay a video source on top of the input.
pad Pad input image to width:height[:x:y[:color]] (default x
and y: 0, default color: black).
pixdesctest Test pixel format definitions.
scale Scale the input video to width:height size and/or convert
the image format.
select Select frames to pass in output.
setdar Set the frame display aspect ratio.
setpts Set PTS for the output video frame.
setsar Set the pixel sample aspect ratio.
settb Set timebase for the output link.
showinfo Show textual information for each video frame.
slicify Pass the images of input video on to next video filter as
split Pass on the input to two outputs.
transpose Transpose input video.
unsharp Sharpen or blur the input video.
vflip Flip the input video vertically.
color Provide an uniformly colored input, syntax is:
movie Read from a movie source.
nullsrc Null video source, never return images.
rgbtestsrc Generate RGB test pattern.
testsrc Generate test pattern.
nullsink Do absolutely nothing with the input video.
buffer Buffer video frames, and make them accessible to the
On Wed, Apr 22, 2015 at 2:30 AM Sampsa Riikonen <sampsa.riikonen at iki.fi>
> Could the out-of-sync result from dropping out corrupt frames? ..
> To re-encode the video, you could try .. (substituting ffmpeg with avconv
> below should work..):
> ffmpeg -i input.mkv -filter_complex "[0:v] fps=25" output.mkv
> .. I think that should enforce fixed frame rate and fix the corrupt frames.
> On 21.04.2015 17:08, Derrell Lipman wrote:
> I have a .mkv file that plays properly using avplay 0.8.17 from Ubuntu
> (with no specified command-line options), but plays with video/audio out of
> sync when using any other program I've tried. I have been unsuccessful at
> finding avconv options that will convert this file to .mp4 with proper
> video/audio sync. *What are the avconv options that are equivalent to the
> defaults of avplay?*
> The file is an hour-long video, so it would be useful, for testing, to
> use the -t option to convert only the first N seconds of the video, but
> that option seems to have no effect.
> Your help will be greatly appreciated! Following is the output of
> avprobe on my .mkv file.
> avprobe version 0.8.17, Copyright (c) 2007-2014 the Libav developers
> built on Apr 21 2015 09:23:53 with gcc 4.6.3
> [matroska,webm @ 0x2450760] Estimating duration from bitrate, this may be
> Input #0, matroska,webm, from '/tmp/11-00-02.mkv':
> ENCODER : Lavf55.33.101
> Duration: 01:13:40.08, start: 0.000000, bitrate: 64 kb/s
> Stream #0.0: Video: h264 (Baseline), yuvj420p, 1920x1080, PAR 1:1 DAR
> 16:9, 60 fps, 19.92 tbr, 1k tbn, 60 tbc (default)
> Stream #0.1: Audio: pcm_mulaw, 8000 Hz, 1 channels, s16, 64 kb/s
> Thank you very much,
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