FFmpeg codec HOWTO - Revision history

Rogerdpack: up to date!

2020-04-25T04:45:45Z

up to date!

← Older revision		Revision as of 21:45, 24 April 2020
Line 67:		Line 67:

	...		...
	~~REGISTER_DECODER(COOK, cook)~~;		extern AVCodec cook_decoder; // must end with _decoder
	...		...

	This ~~macro expands to~~ a ~~register_avcodec~~(~~) call which registers a codec for internal use~~.		This is expanded at configure time into a REGISTER_CODEC(...)
	~~Note that register_avcodec(~~) ~~will only be called when CONFIG_COOK_DECODER is defined.~~
	~~This allows to not compile the decoder code for a specific codec.~~		configure accomplishes this by running something like:
	~~But where is it defined? This is extracted by~~ configure ~~with~~ this ~~command line~~:

	sed -n 's/^[^#]DEC., \(.\)).*/\1_decoder/p' libavcodec/allcodecs.c		sed -n 's/^[^#]DEC., \(.\)).*/\1_decoder/p' libavcodec/allcodecs.c

	So adding ~~a REGISTER_DECODER(NEW, new)~~ entry in allcodecs.c and reconfigure is enough to add the needed define. Now we have everything to hookup a codec.		So adding an entry in allcodecs.c and reconfigure is enough to add the needed define. Now we have everything to hookup a codec.

	=== libavcodec/Makefile ===		=== libavcodec/Makefile ===

Rogerdpack: /* trouble shooting */

2015-10-13T23:50:10Z

trouble shooting

← Older revision		Revision as of 16:50, 13 October 2015
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	meant "your first member of your Context struct needs to be an AVClass *"		meant "your first member of your Context struct needs to be an AVClass *"

			if it works but just says ""0 packets muxed"" you need to set the *got_packet return value to "1" or the muxer won't mux what you're giving it

	== see also ==		== see also ==

Rogerdpack: add link

2015-10-13T21:15:53Z

add link

← Older revision		Revision as of 14:15, 13 October 2015
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	* [[FFmpeg demuxer howto]]		* [[FFmpeg demuxer howto]]
	* [[FFmpeg programming conventions]]		* [[FFmpeg programming conventions]]
			* [[FFmpeg_filter_HOWTO]]

	[[Category:FFmpeg Tutorials]]		[[Category:FFmpeg Tutorials]]
	[[Category:Tutorials]]		[[Category:Tutorials]]

Rogerdpack: /* trouble shooting */

2015-10-13T21:06:10Z

trouble shooting

← Older revision		Revision as of 14:06, 13 October 2015
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	meant encoder's description		meant encoder's description
	.pix_fmts needs to end with AV_PIX_FMT_NONE		.pix_fmts needs to end with AV_PIX_FMT_NONE

			Assertion (const AVClass *)avctx->priv_data == codec->priv_class failed at libavcodec/utils.c:1554

			meant "your first member of your Context struct needs to be an AVClass *"

	== see also ==		== see also ==

Rogerdpack at 19:12, 13 October 2015

2015-10-13T19:12:29Z

← Older revision		Revision as of 12:12, 13 October 2015
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	<span style="color: #000000;"> .decode = glue_decode_frame,</span>		<span style="color: #000000;"> .decode = glue_decode_frame,</span>
	<span style="color: #000000;">};</span>		<span style="color: #000000;">};</span>

			=== trouble shooting ===
			Invalid pixel format '(null)'
			Output pad "default" with type video of the filter instance "Parsed_null_0" of null not connected to any destination
			Error opening filters!

			meant encoder's description
			.pix_fmts needs to end with AV_PIX_FMT_NONE

	== see also ==		== see also ==

DonDiego: FFmpeg codec howto moved to FFmpeg codec HOWTO: Fix title spelling.

2010-07-08T13:47:35Z

FFmpeg codec howto moved to FFmpeg codec HOWTO: Fix title spelling.

← Older revision	Revision as of 06:47, 8 July 2010
(No difference)

Compn: /* The Glue codec template */ properly format comment

2009-02-18T15:57:26Z

The Glue codec template: properly format comment

Compn: /* The Glue codec template */ typo

2009-02-18T15:54:53Z

The Glue codec template: typo

← Older revision		Revision as of 08:54, 18 February 2009
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	should be made so that the output quality is maximized.		should be made so that the output quality is maximized.
	This means that if undamaged data is assumed then unused/resereved values		This means that if undamaged data is assumed then unused/resereved values
	should lead to warnings but not failure. (~~assumtion~~ of slightly non compliant		should lead to warnings but not failure. (assumption of slightly non compliant
	file)		file)
	OTOH if possibly damaged data is assumed and it is assumed that the original		OTOH if possibly damaged data is assumed and it is assumed that the original
Line 265:		Line 265:
	values should trigger error concealment code and the decoder/demuxer should		values should trigger error concealment code and the decoder/demuxer should
	attempt to resync.		attempt to resync.
	The ~~decission~~ between these 2 should be made by using		The decision between these 2 should be made by using
	AVCodecContext.error_recognition unless its a clear case where only one of		AVCodecContext.error_recognition unless its a clear case where only one of
	the 2 makes sense.		the 2 makes sense.

Compn: /* The Glue codec template */ add comment about error concealment

2009-02-18T15:52:57Z

The Glue codec template: add comment about error concealment

@@ Line 255: / Line 255: @@
   <span style="color: #000000;">        </span><span style="font-weight: bold;color: #000000;">return</span><span style="color: #000000;"> -</span><span style="color: #0000ff;">1</span><span style="color: #000000;">;</span>
   <span style="color: #000000;">    }</span>
   <span style="color: #000000;">    </span><span style="font-style: italic;color: #808080;">/* Return the amount of bytes consumed if everything was ok */</span>

Benoit: cosmetics: add spaces to AVCodec structure fields

2009-01-27T07:57:47Z

cosmetics: add spaces to AVCodec structure fields

← Older revision		Revision as of 00:57, 27 January 2009
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	<span style="color: #000000;">AVCodec glue_decoder =</span>		<span style="color: #000000;">AVCodec glue_decoder =</span>
	<span style="color: #000000;">{</span>		<span style="color: #000000;">{</span>
	<span style="color: #000000;"> .name = </span><span style="color: #dd0000;">"glue"</span><span style="color: #000000;">,</span>		<span style="color: #000000;"> .name = </span><span style="color: #dd0000;">"glue"</span><span style="color: #000000;">,</span>
	<span style="color: #000000;"> .type = CODEC_TYPE_AUDIO,</span>		<span style="color: #000000;"> .type = CODEC_TYPE_AUDIO,</span>
	<span style="color: #000000;"> .id = CODEC_ID_GLUE,</span>		<span style="color: #000000;"> .id = CODEC_ID_GLUE,</span>
	<span style="color: #000000;"> .priv_data_size = </span><span style="font-weight: bold;color: #000000;">sizeof</span><span style="color: #000000;">(GLUEContext),</span>		<span style="color: #000000;"> .priv_data_size = </span><span style="font-weight: bold;color: #000000;">sizeof</span><span style="color: #000000;">(GLUEContext),</span>
	<span style="color: #000000;"> .init = glue_decode_init,</span>		<span style="color: #000000;"> .init = glue_decode_init,</span>
	<span style="color: #000000;"> .close = glue_decode_close,</span>		<span style="color: #000000;"> .close = glue_decode_close,</span>
	<span style="color: #000000;"> .decode = glue_decode_frame,</span>		<span style="color: #000000;"> .decode = glue_decode_frame,</span>
	<span style="color: #000000;">};</span>		<span style="color: #000000;">};</span>

← Older revision		Revision as of 08:57, 18 February 2009
Line 257:		Line 257:
	<span style="font-style: italic;color: #808080;">		<span style="font-style: italic;color: #808080;">
	/* The decision between erroring out or not in case of unexpected data		/* The decision between erroring out or not in case of unexpected data
	should be made so that the output quality is maximized.		should be made so that the output quality is maximized.
	This means that if undamaged data is assumed then unused/resereved values		This means that if undamaged data is assumed then unused/resereved values
	should lead to warnings but not failure. (assumption of slightly non compliant		should lead to warnings but not failure. (assumption of slightly non compliant
	file)		file)
	OTOH if possibly damaged data is assumed and it is assumed that the original		OTOH if possibly damaged data is assumed and it is assumed that the original
	did contain specific values in reserved/unused fields then finding unexpected		did contain specific values in reserved/unused fields then finding unexpected
	values should trigger error concealment code and the decoder/demuxer should		values should trigger error concealment code and the decoder/demuxer should
	attempt to resync.		attempt to resync.
	The decision between these 2 should be made by using		The decision between these 2 should be made by using
	AVCodecContext.error_recognition unless its a clear case where only one of		AVCodecContext.error_recognition unless its a clear case where only one of
	the 2 makes sense.		the 2 makes sense.
	*/		*/
	</span>		</span>