[FFmpeg-devel] [PATCH] write AC-3 metadata

Justin Ruggles justin.ruggles
Wed Dec 22 02:25:02 CET 2010

On 12/21/2010 06:13 PM, Justin Ruggles wrote:

> On 12/21/2010 05:20 PM, Kieran Kunhya wrote:
>>> Date: Tuesday, 21 December, 2010, 21:56
>>> Hi,
>>> This patch adds writing of AC-3 metadata to the AC-3
>>> encoder.
>>> I chose to use AVOption instead of trying to move the
>>> metadata API to
>>> libavcodec because the AC-3 metadata isn't just regular
>>> metadata.  Even
>>> though it is not audio data, many of the fields actually
>>> affect decoding.
>>> Some of the options use integers to set a specific code
>>> value rather
>>> than using a float value directly (e.g. mixing
>>> levels).  It looks a bit
>>> ugly, but I chose to do this because there are only a few
>>> valid values.
>>>  Trying to determine which value the user wants by
>>> comparing floats
>>> seems more complicated.  Plus this allows the help
>>> text to tell the user
>>> what the valid values are for those options.
>>> Thanks,
>>> Justin
>> Is there any possibility of making these metadata options changeable per frame? Quite useful for broadcast applications when the metadata needs to be different during advertising or during specific programming.
> If you're changing programs, you should probably re-initialize encoding
> anyway.  Other things can change too like bitrate, number of channels,
> etc...
> As for setting metadata per-frame, it is possible.  New patch attached.
>  It adds an option to enable per-frame validation of metadata so that it
> won't significantly affect performance when the option is not enabled.

oops. disregard this patch. i forgot the most important part. i'll send
a new one in a little while.


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