[FFmpeg-user] Concat input protocol: more files, more missing streams

Paul B Mahol onemda at gmail.com
Sat Sep 14 18:11:22 CEST 2013

On 9/14/13, Thierry Lelegard <thierry.lelegard at free.fr> wrote:
> Hello,
> I try to use the "concat:" input protocol to process at once
> a movie from a ripped DVD which is split over several VOB files.
> But the more files I add in the input specification, the more
> input streams are undetected. Playing with -probesize does not
> change anything.
> Let's take an example. Consider the content of a ripped DVD
> ("Cat on a hot tin roof"). The main movie is split over 5 files,
> VTS_01_1.VOB to VTS_01_5.VOB.
> There is for sure one DVDNAV stream and one video stream.
> Audio streams: Both ffmpeg and MediaInfo find 3 audio streams.
> Dumping the IFO file, a fourth audio stream is referenced
> with "en" language while audio #0 was already "en"
> Subpicture streams: ffmpeg finds 10 streams while MediaInfo finds 12.
> Dumping the IFO file, 12 subpicture streams are referenced but the
> last two are "en" and "it" again, same as #0 and #2.
> Anyway, now let's focus on ffmpeg -i concat: inconsistencies.
> When you try ffmpeg on the first VOB only (with or without "concat:"),
> all 15 streams are found. When you try ffmpeg with "concat:" over the
> first 2 files, only 14 streams are found (one subtitle stream disappeared).
> And when you try with "concat:" on the first 3 files, only 5 streams are
> found (all subtitle streams disappeared). See full commands and outputs
> below, including ffmpeg version.
> The tests are made with 10 MB as probe size. But using any other size, from
> the default size to 100 MB, does not change anything.
> The simple test commands below do not use the subtitle streams. But this is
> just to illustrate the problem. In the real world, I want to concat all
> five
> VOB files and burn the french subtitles into the video. But ffmpeg does not
> detect the subtitle stream with all VOB concatenated.
> Any idea?

Perhaps you actually need -analyzeduration ?

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