[FFmpeg-user] keeping subtitles while transcoding

[Rick C.]

On Jan 19, 2012, at 5:17 AM, Bernhard Rohrer wrote:

> OK, got it
> 
> $ffmpeg -i Seven.Samurai.1954.MULTiSUBS.1080p.BluRay.x264-HDZ.mkv  -vcodec mpeg4 -pass 1 -threads 2 -b:v 10000000  -scodec copy -map 0 -map -0:2 -map -0:4 -acodec ac3 -b:a 384000 -f matroska -y /dev/null
> 
> mp4 clearly doesn't support subtitles
> 
> /B
> 
> On 18/01/12 17:46, graylion wrote:
>> Hiya
>> 
>> I have googled high and low and am not finding this:
>> 
>> I have a file with h264 video and audio and subtitles. I want to transcode
>> the h264 into mp4 while keeping the rest intact.
>> 
>> my commandline looks like this:
>> 
>> ffmpeg -i Seven.Samurai.1954.MULTiSUBS.1080p.BluRay.x264-HDZ.mkv  -vcodec
>> mpeg4 -pass 1 -threads 2 -b:v 10000000 -scodec copy -an -f mp4 -y /dev/null
>> 
>> this leads to
>> 
>> Stream mapping:
>>   Stream #0.0 ->  #0.0 (h264 ->  mpeg4)
>>   Stream #0.2 ->  #0.1 (copy)
>> Could not write header for output file #0 (incorrect codec parameters ?)
>> 
>> which also are the wrong streams, since i want to map 0.3 which are the
>> English subtitles. also i am entirely unclear as to how I would go about
>> mapping a second pass.
>> 
>> Any help appreciated.
>> 
>> --

I had this same question/problem actually.  I think .mp4 does support subtitles, but coming from .mkv using -scodec copy doesn't seem to work.  If you go from .mp4 to .mp4 using -scodec copy it works.  I'm not quite sure what else is possible when using -scodec to make this work, but if there's a way it would be great to hear.  Thanks!

rc