[FFmpeg-devel] [PATCH 2/2] lavf: Add WebM DASH Manifest Muxer

[Vignesh Venkatasubramanian]

On Thu, Jul 10, 2014 at 1:26 PM, Michael Niedermayer <michaelni at gmx.at> wrote:
> On Thu, Jul 10, 2014 at 01:12:20PM -0700, Vignesh Venkatasubramanian wrote:
>> On Thu, Jul 10, 2014 at 12:58 PM, Michael Niedermayer <michaelni at gmx.at> wrote:
>> > On Mon, Jul 07, 2014 at 01:41:34PM -0700, Vignesh Venkatasubramanian wrote:
>> >> This patch adds the ability to generate WebM DASH manifest XML using
>> >> ffmpeg. A sample command line would be as follows:
>> >>
>> >> ffmpeg \
>> >>   -f webm_dash_manifest -i video1.webm \
>> >>   -f webm_dash_manifest -i video2.webm \
>> >>   -f webm_dash_manifest -i audio1.webm \
>> >>   -f webm_dash_manifest -i audio2.webm \
>> >>   -map 0 -map 1 -map 2 -map 3 \
>> >>   -c copy \
>> >>   -f webm_dash_manifest \
>> >>   -adaptation_sets “id=0,streams=0,1 id=1,streams=2,3” \
>> >>   manifest.xml
>> >>
>> >> It works by exporting necessary fields as metadata tags in matroskadec
>> >> and use those values to write the appropriate XML fields as per the WebM
>> >> DASH Specification [1]. Some ideas are adopted from webm-tools project
>> >> [2].
>> >>
>> >> [1]
>> >> https://sites.google.com/a/webmproject.org/wiki/adaptive-streaming/webm-dash-specification
>> >> [2]
>> >> https://chromium.googlesource.com/webm/webm-tools/+/master/webm_dash_manifest/
>> >>
>> >> Signed-off-by: Vignesh Venkatasubramanian <vigneshv at google.com>
>> >
>> > what if the input is not webm but lets say mpeg-ts ?
>>
>> not sure what you mean here, the muxer is only for generating DASH
>> Manifest for WebM files.
>
> well, i mean that if you feed it from mpeg-ts it would generate
> webm files and a manifest
> similar to what our hls muxer would do
> i understand it doesnt do that but i dont understand why
>
> would it have a disadvantage if it worked that way ?
>

that would be the ideal case. but i could not figure out how to
achieve that. (i.e.) take multiple audio/video files of any format ->
convert them to multiple audio/video WebM files and generate the
manifest in one step. using this muxer one can get there in two steps.
first one to convert the audio/video streams to WebM and the second
one to generate the manifest. Generating the manifest is not possible
before the WebM file is fully generated.

> [...]
>
> --
> Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB
>
> During times of universal deceit, telling the truth becomes a
> revolutionary act. -- George Orwell
>
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-- 
Vignesh