FFmpeg interface improvements

This patch changes a couple of things in the video output encoding.

{F362527}

- Clearer separation between container and codec. No more "format", as this is
  too ambiguous. As a result, codecs were removed from the container list.
- Added FFmpeg speed presets, so the user can choosen from the range "Very
  slow" to "Ultra fast". By default no preset is used.
- Added Constant Rate Factor (CRF) mode, which allows changing the bit-rate
  depending on the desired quality and the input. This generally produces the
  best quality videos, at the expense of not knowing the exact bit-rate and
  file size.
- Added optional maximum of non-B-frames between B-frames (`max_b_frames`).
- Presets were adjusted for these changes, and new presets added. One of the
  new presets is [recommended](https://trac.ffmpeg.org/wiki/Encode/VFX#H.264)
  for reviewing videos, as it allows players to scrub through it easily. Might
  be nice in weeklies. This preset also requires control over the
  `max_b_frames` setting.

GUI-only changes:
- Renamed "MPEG" in the output file format menu with "FFmpeg", as this is more
  accurate. After all, FFmpeg is used when this option is chosen, which can
  also output non-MPEG files.
- Certain parts of the GUI are disabled when not in use:
    - bit rate options are not used when a constant rate factor is given.
    - audio bitrate & volume are not used when no audio is exported.

Note that I did not touch `BKE_ffmpeg_preset_set()`. There are currently two
preset systems for FFmpeg (`BKE_ffmpeg_preset_set()` and the Python preset
system). Before we do more work on `BKE_ffmpeg_preset_set()`, I think it's a
good idea to determine whether we want to keep it at all.

After this patch has been accepted, I'd be happy to go through the code and
remove any then-obsolete bits, such as the handling of "XVID" as a container
format.

Reviewers: sergey, mont29, brecht

Subscribers: mpan3, Blendify, brecht, fsiddi

Tags: #bf_blender

Differential Revision: https://developer.blender.org/D2242

5 files changed, 177 insertions, 33 deletions

diff --git a/source/blender/blenkernel/intern/image.c b/source/blender/blenkernel/intern/image.c
index 8a9cb73c8c9..a4eef2f9230 100644
--- a/source/blender/blenkernel/intern/image.c
+++ b/source/blender/blenkernel/intern/image.c
@@ -1325,7 +1325,7 @@ char BKE_imtype_from_arg(const char *imtype_arg)
 	else if (STREQ(imtype_arg, "EXR")) return R_IMF_IMTYPE_OPENEXR;
 	else if (STREQ(imtype_arg, "MULTILAYER")) return R_IMF_IMTYPE_MULTILAYER;
 #endif
-	else if (STREQ(imtype_arg, "MPEG")) return R_IMF_IMTYPE_FFMPEG;
+	else if (STREQ(imtype_arg, "FFMPEG")) return R_IMF_IMTYPE_FFMPEG;
 	else if (STREQ(imtype_arg, "FRAMESERVER")) return R_IMF_IMTYPE_FRAMESERVER;
 #ifdef WITH_CINEON
 	else if (STREQ(imtype_arg, "CINEON")) return R_IMF_IMTYPE_CINEON;
diff --git a/source/blender/blenkernel/intern/writeffmpeg.c b/source/blender/blenkernel/intern/writeffmpeg.c
index de55a1977bf..b0ab6f707fa 100644
--- a/source/blender/blenkernel/intern/writeffmpeg.c
+++ b/source/blender/blenkernel/intern/writeffmpeg.c
@@ -69,10 +69,14 @@ typedef struct FFMpegContext {
 	int ffmpeg_video_bitrate;
 	int ffmpeg_audio_bitrate;
 	int ffmpeg_gop_size;
+	int ffmpeg_max_b_frames;
 	int ffmpeg_autosplit;
 	int ffmpeg_autosplit_count;
 	bool ffmpeg_preview;
 
+	int ffmpeg_crf;  /* set to 0 to not use CRF mode; we have another flag for lossless anyway. */
+	int ffmpeg_preset; /* see FFMpegPreset */
+
 	AVFormatContext *outfile;
 	AVStream *video_stream;
 	AVStream *audio_stream;
@@ -560,10 +564,37 @@ static AVStream *alloc_video_stream(FFMpegContext *context, RenderData *rd, int
 	}
 	
 	c->gop_size = context->ffmpeg_gop_size;
-	c->bit_rate = context->ffmpeg_video_bitrate * 1000;
-	c->rc_max_rate = rd->ffcodecdata.rc_max_rate * 1000;
-	c->rc_min_rate = rd->ffcodecdata.rc_min_rate * 1000;
-	c->rc_buffer_size = rd->ffcodecdata.rc_buffer_size * 1024;
+	c->max_b_frames = context->ffmpeg_max_b_frames;
+
+	if (context->ffmpeg_crf >= 0) {
+		ffmpeg_dict_set_int(&opts, "crf", context->ffmpeg_crf);
+	} else {
+		c->bit_rate = context->ffmpeg_video_bitrate * 1000;
+		c->rc_max_rate = rd->ffcodecdata.rc_max_rate * 1000;
+		c->rc_min_rate = rd->ffcodecdata.rc_min_rate * 1000;
+		c->rc_buffer_size = rd->ffcodecdata.rc_buffer_size * 1024;
+	}
+
+	if (context->ffmpeg_preset) {
+		char const * preset_name;
+		switch(context->ffmpeg_preset) {
+			case FFM_PRESET_ULTRAFAST: preset_name = "ultrafast"; break;
+			case FFM_PRESET_SUPERFAST: preset_name = "superfast"; break;
+			case FFM_PRESET_VERYFAST: preset_name = "veryfast"; break;
+			case FFM_PRESET_FASTER: preset_name = "faster"; break;
+			case FFM_PRESET_FAST: preset_name = "fast"; break;
+			case FFM_PRESET_MEDIUM: preset_name = "medium"; break;
+			case FFM_PRESET_SLOW: preset_name = "slow"; break;
+			case FFM_PRESET_SLOWER: preset_name = "slower"; break;
+			case FFM_PRESET_VERYSLOW: preset_name = "veryslow"; break;
+			default:
+				printf("Unknown preset number %i, ignoring.\n", context->ffmpeg_preset);
+				preset_name = NULL;
+		}
+		if (preset_name != NULL) {
+			av_dict_set(&opts, "preset", preset_name, 0);
+		}
+	}
 
 #if 0
 	/* this options are not set in ffmpeg.c and leads to artifacts with MPEG-4
@@ -819,6 +850,12 @@ static int start_ffmpeg_impl(FFMpegContext *context, struct RenderData *rd, int
 	context->ffmpeg_audio_bitrate = rd->ffcodecdata.audio_bitrate;
 	context->ffmpeg_gop_size = rd->ffcodecdata.gop_size;
 	context->ffmpeg_autosplit = rd->ffcodecdata.flags & FFMPEG_AUTOSPLIT_OUTPUT;
+	context->ffmpeg_crf = rd->ffcodecdata.constant_rate_factor;
+	context->ffmpeg_preset = rd->ffcodecdata.ffmpeg_preset;
+
+	if ((rd->ffcodecdata.flags & FFMPEG_USE_MAX_B_FRAMES) != 0) {
+		context->ffmpeg_max_b_frames = rd->ffcodecdata.max_b_frames;
+	}
 
 	/* Determine the correct filename */
 	ffmpeg_filepath_get(context, name, rd, context->ffmpeg_preview, suffix);
@@ -852,12 +889,16 @@ static int start_ffmpeg_impl(FFMpegContext *context, struct RenderData *rd, int
 	/* Returns after this must 'goto fail;' */
 
 	of->oformat = fmt;
-	of->packet_size = rd->ffcodecdata.mux_packet_size;
-	if (context->ffmpeg_audio_codec != AV_CODEC_ID_NONE) {
-		ffmpeg_dict_set_int(&opts, "muxrate", rd->ffcodecdata.mux_rate);
-	}
-	else {
-		av_dict_set(&opts, "muxrate", "0", 0);
+
+	/* Only bother with setting packet size & mux rate when CRF is not used. */
+	if (context->ffmpeg_crf == 0) {
+		of->packet_size = rd->ffcodecdata.mux_packet_size;
+		if (context->ffmpeg_audio_codec != AV_CODEC_ID_NONE) {
+			ffmpeg_dict_set_int(&opts, "muxrate", rd->ffcodecdata.mux_rate);
+		}
+		else {
+			av_dict_set(&opts, "muxrate", "0", 0);
+		}
 	}
 
 	ffmpeg_dict_set_int(&opts, "preload", (int)(0.5 * AV_TIME_BASE));
@@ -1503,14 +1544,6 @@ static void ffmpeg_set_expert_options(RenderData *rd)
 		BKE_ffmpeg_property_add_string(rd, "video", "fast-pskip:1");
 		BKE_ffmpeg_property_add_string(rd, "video", "wpredp:2");
 #endif
-
-		if (rd->ffcodecdata.flags & FFMPEG_LOSSLESS_OUTPUT) {
-#ifdef FFMPEG_HAVE_DEPRECATED_FLAGS2
-			BKE_ffmpeg_property_add_string(rd, "video", "cqp:0");
-#else
-			BKE_ffmpeg_property_add_string(rd, "video", "qp:0");
-#endif
-		}
 	}
 	else if (codec_id == AV_CODEC_ID_DNXHD) {
 		if (rd->ffcodecdata.flags & FFMPEG_LOSSLESS_OUTPUT)
@@ -1622,9 +1655,10 @@ void BKE_ffmpeg_image_type_verify(RenderData *rd, ImageFormatData *imf)
 		    rd->ffcodecdata.audio_codec <= 0 ||
 		    rd->ffcodecdata.video_bitrate <= 1)
 		{
-			rd->ffcodecdata.codec = AV_CODEC_ID_MPEG2VIDEO;
-
-			BKE_ffmpeg_preset_set(rd, FFMPEG_PRESET_DVD);
+			BKE_ffmpeg_preset_set(rd, FFMPEG_PRESET_H264);
+			rd->ffcodecdata.constant_rate_factor = FFM_CRF_MEDIUM;
+			rd->ffcodecdata.ffmpeg_preset = FFM_PRESET_MEDIUM;
+			rd->ffcodecdata.type = FFMPEG_MKV;
 		}
 		if (rd->ffcodecdata.type == FFMPEG_OGG) {
 			rd->ffcodecdata.type = FFMPEG_MPEG2;
diff --git a/source/blender/blenloader/intern/versioning_270.c b/source/blender/blenloader/intern/versioning_270.c
index dfaa59c4e3f..aa5ef1c98cf 100644
--- a/source/blender/blenloader/intern/versioning_270.c
+++ b/source/blender/blenloader/intern/versioning_270.c
@@ -1392,4 +1392,18 @@ void blo_do_versions_270(FileData *fd, Library *UNUSED(lib), Main *main)
 			}
 		}
 	}
+	if (!MAIN_VERSION_ATLEAST(main, 279, 0)) {
+		if (!DNA_struct_elem_find(fd->filesdna, "FFMpegCodecData", "int", "ffmpeg_preset")) {
+			for (Scene *scene = main->scene.first; scene; scene = scene->id.next) {
+				/* "medium" is the preset FFmpeg uses when no presets are given. */
+				scene->r.ffcodecdata.ffmpeg_preset = FFM_PRESET_MEDIUM;
+			}
+		}
+		if (!DNA_struct_elem_find(fd->filesdna, "FFMpegCodecData", "int", "constant_rate_factor")) {
+			for (Scene *scene = main->scene.first; scene; scene = scene->id.next) {
+				/* fall back to behaviour from before we introduced CRF for old files */
+				scene->r.ffcodecdata.constant_rate_factor = FFM_CRF_NONE;
+			}
+		}
+	}
 }
diff --git a/source/blender/makesdna/DNA_scene_types.h b/source/blender/makesdna/DNA_scene_types.h
index 5c5264afcba..94f23197293 100644
--- a/source/blender/makesdna/DNA_scene_types.h
+++ b/source/blender/makesdna/DNA_scene_types.h
@@ -135,6 +135,37 @@ typedef struct QuicktimeCodecSettings {
 	int pad1;
 } QuicktimeCodecSettings;
 
+typedef enum FFMpegPreset {
+	FFM_PRESET_NONE,
+	FFM_PRESET_ULTRAFAST,
+	FFM_PRESET_SUPERFAST,
+	FFM_PRESET_VERYFAST,
+	FFM_PRESET_FASTER,
+	FFM_PRESET_FAST,
+	FFM_PRESET_MEDIUM,
+	FFM_PRESET_SLOW,
+	FFM_PRESET_SLOWER,
+	FFM_PRESET_VERYSLOW,
+} FFMpegPreset;
+
+
+/* Mapping from easily-understandable descriptions to CRF values.
+ * Assumes we output 8-bit video. Needs to be remapped if 10-bit
+ * is output.
+ * We use a slightly wider than "subjectively sane range" according
+ * to https://trac.ffmpeg.org/wiki/Encode/H.264#a1.ChooseaCRFvalue
+ */
+typedef enum FFMpegCrf {
+	FFM_CRF_NONE = -1,
+	FFM_CRF_LOSSLESS = 0,
+	FFM_CRF_PERC_LOSSLESS = 17,
+	FFM_CRF_HIGH = 20,
+	FFM_CRF_MEDIUM = 23,
+	FFM_CRF_LOW = 26,
+	FFM_CRF_VERYLOW = 29,
+	FFM_CRF_LOWEST = 32,
+} FFMpegCrf;
+
 typedef struct FFMpegCodecData {
 	int type;
 	int codec;
@@ -146,13 +177,18 @@ typedef struct FFMpegCodecData {
 	int audio_pad;
 	float audio_volume;
 	int gop_size;
+	int max_b_frames; /* only used if FFMPEG_USE_MAX_B_FRAMES flag is set. */
 	int flags;
+	int constant_rate_factor;
+	int ffmpeg_preset; /* see FFMpegPreset */
 
 	int rc_min_rate;
 	int rc_max_rate;
 	int rc_buffer_size;
 	int mux_packet_size;
 	int mux_rate;
+	int pad1;
+
 	IDProperty *properties;
 } FFMpegCodecData;
 
@@ -1982,6 +2018,7 @@ enum {
 #endif
 	FFMPEG_AUTOSPLIT_OUTPUT = 2,
 	FFMPEG_LOSSLESS_OUTPUT  = 4,
+	FFMPEG_USE_MAX_B_FRAMES = (1 << 3),
 };
 
 /* Paint.flags */
diff --git a/source/blender/makesrna/intern/rna_scene.c b/source/blender/makesrna/intern/rna_scene.c
index bd6674f899c..c63d4e775f8 100644
--- a/source/blender/makesrna/intern/rna_scene.c
+++ b/source/blender/makesrna/intern/rna_scene.c
@@ -282,16 +282,11 @@ EnumPropertyItem rna_enum_image_type_items[] = {
 	{R_IMF_IMTYPE_FRAMESERVER, "FRAMESERVER", ICON_FILE_SCRIPT, "Frame Server", "Output image to a frameserver"},
 #endif
 #ifdef WITH_FFMPEG
-	{R_IMF_IMTYPE_H264, "H264", ICON_FILE_MOVIE, "H.264", "Output video in H.264 format"},
-	{R_IMF_IMTYPE_FFMPEG, "FFMPEG", ICON_FILE_MOVIE, "MPEG", "Output video in MPEG format"},
-	{R_IMF_IMTYPE_THEORA, "THEORA", ICON_FILE_MOVIE, "Ogg Theora", "Output video in Ogg format"},
+	{R_IMF_IMTYPE_FFMPEG, "FFMPEG", ICON_FILE_MOVIE, "FFmpeg video", "The most versatile way to output video files"},
 #endif
 #ifdef WITH_QUICKTIME
 	{R_IMF_IMTYPE_QUICKTIME, "QUICKTIME", ICON_FILE_MOVIE, "QuickTime", "Output video in Quicktime format"},
 #endif
-#ifdef WITH_FFMPEG
-	{R_IMF_IMTYPE_XVID, "XVID", ICON_FILE_MOVIE, "Xvid", "Output video in Xvid format"},
-#endif
 	{0, NULL, 0, NULL, NULL}
 };
 
@@ -5320,6 +5315,7 @@ static void rna_def_scene_ffmpeg_settings(BlenderRNA *brna)
 	PropertyRNA *prop;
 
 #ifdef WITH_FFMPEG
+	/* Container types */
 	static EnumPropertyItem ffmpeg_format_items[] = {
 		{FFMPEG_MPEG1, "MPEG1", 0, "MPEG-1", ""},
 		{FFMPEG_MPEG2, "MPEG2", 0, "MPEG-2", ""},
@@ -5327,8 +5323,8 @@ static void rna_def_scene_ffmpeg_settings(BlenderRNA *brna)
 		{FFMPEG_AVI, "AVI", 0, "AVI", ""},
 		{FFMPEG_MOV, "QUICKTIME", 0, "Quicktime", ""},
 		{FFMPEG_DV, "DV", 0, "DV", ""},
-		{FFMPEG_H264, "H264", 0, "H.264", ""},
-		{FFMPEG_XVID, "XVID", 0, "Xvid", ""},
+//		{FFMPEG_H264, "H264", 0, "H.264", ""},  not a container
+//		{FFMPEG_XVID, "XVID", 0, "Xvid", ""},   not a container
 		{FFMPEG_OGG, "OGG", 0, "Ogg", ""},
 		{FFMPEG_MKV, "MKV", 0, "Matroska", ""},
 		{FFMPEG_FLV, "FLASH", 0, "Flash", ""},
@@ -5352,6 +5348,32 @@ static void rna_def_scene_ffmpeg_settings(BlenderRNA *brna)
 		{0, NULL, 0, NULL, NULL}
 	};
 
+	static EnumPropertyItem ffmpeg_preset_items[] = {
+		{FFM_PRESET_ULTRAFAST, "ULTRAFAST", 0, "Ultra fast; biggest file", ""},
+		{FFM_PRESET_SUPERFAST, "SUPERFAST", 0, "Super fast", ""},
+		{FFM_PRESET_VERYFAST, "VERYFAST", 0, "Very fast", ""},
+		{FFM_PRESET_FASTER, "FASTER", 0, "Faster", ""},
+		{FFM_PRESET_FAST, "FAST", 0, "Fast", ""},
+		{FFM_PRESET_MEDIUM, "MEDIUM", 0, "Medium speed", ""},
+		{FFM_PRESET_SLOW, "SLOW", 0, "Slow", ""},
+		{FFM_PRESET_SLOWER, "SLOWER", 0, "Slower", ""},
+		{FFM_PRESET_VERYSLOW, "VERYSLOW", 0, "Very slow; smallest file", ""},
+		{0, NULL, 0, NULL, NULL}
+	};
+
+	static EnumPropertyItem ffmpeg_crf_items[] = {
+		{FFM_CRF_NONE, "NONE", 0, "None; use constant bit-rate",
+		 "Use constant bit rate, rather than constant output quality"},
+		{FFM_CRF_LOSSLESS, "LOSSLESS", 0, "Lossless", ""},
+		{FFM_CRF_PERC_LOSSLESS, "PERC_LOSSLESS", 0, "Perceptually lossless", ""},
+		{FFM_CRF_HIGH, "HIGH", 0, "High quality", ""},
+		{FFM_CRF_MEDIUM, "MEDIUM", 0, "Medium quality", ""},
+		{FFM_CRF_LOW, "LOW", 0, "Low quality", ""},
+		{FFM_CRF_VERYLOW, "VERYLOW", 0, "Very low quality", ""},
+		{FFM_CRF_LOWEST, "LOWEST", 0, "Lowest quality", ""},
+		{0, NULL, 0, NULL, NULL}
+	};
+
 	static EnumPropertyItem ffmpeg_audio_codec_items[] = {
 		{AV_CODEC_ID_NONE, "NONE", 0, "None", ""},
 		{AV_CODEC_ID_MP2, "MP2", 0, "MP2", ""},
@@ -5383,13 +5405,15 @@ static void rna_def_scene_ffmpeg_settings(BlenderRNA *brna)
 	RNA_def_property_enum_bitflag_sdna(prop, NULL, "type");
 	RNA_def_property_clear_flag(prop, PROP_ANIMATABLE);
 	RNA_def_property_enum_items(prop, ffmpeg_format_items);
-	RNA_def_property_ui_text(prop, "Format", "Output file format");
+	RNA_def_property_enum_default(prop, FFMPEG_MKV);
+	RNA_def_property_ui_text(prop, "Container", "Output file container");
 	RNA_def_property_update(prop, NC_SCENE | ND_RENDER_OPTIONS, "rna_FFmpegSettings_codec_settings_update");
 
 	prop = RNA_def_property(srna, "codec", PROP_ENUM, PROP_NONE);
 	RNA_def_property_enum_bitflag_sdna(prop, NULL, "codec");
 	RNA_def_property_clear_flag(prop, PROP_ANIMATABLE);
 	RNA_def_property_enum_items(prop, ffmpeg_codec_items);
+	RNA_def_property_enum_default(prop, AV_CODEC_ID_H264);
 	RNA_def_property_ui_text(prop, "Codec", "FFmpeg codec to use");
 	RNA_def_property_update(prop, NC_SCENE | ND_RENDER_OPTIONS, "rna_FFmpegSettings_codec_settings_update");
 
@@ -5421,8 +5445,25 @@ static void rna_def_scene_ffmpeg_settings(BlenderRNA *brna)
 	prop = RNA_def_property(srna, "gopsize", PROP_INT, PROP_NONE);
 	RNA_def_property_int_sdna(prop, NULL, "gop_size");
 	RNA_def_property_clear_flag(prop, PROP_ANIMATABLE);
-	RNA_def_property_range(prop, 0, 100);
-	RNA_def_property_ui_text(prop, "GOP Size", "Distance between key frames");
+	RNA_def_property_range(prop, 0, 500);
+	RNA_def_property_int_default(prop, 25);
+	RNA_def_property_ui_text(prop, "Keyframe interval",
+	                         "Distance between key frames, also known as GOP size; "
+	                         "influences file size and seekability");
+	RNA_def_property_update(prop, NC_SCENE | ND_RENDER_OPTIONS, NULL);
+
+	prop = RNA_def_property(srna, "max_b_frames", PROP_INT, PROP_NONE);
+	RNA_def_property_int_sdna(prop, NULL, "max_b_frames");
+	RNA_def_property_clear_flag(prop, PROP_ANIMATABLE);
+	RNA_def_property_range(prop, 0, 16);
+	RNA_def_property_ui_text(prop, "Max B-frames",
+	                         "Maximum number of B-frames between non-B-frames; influences file size and seekability");
+	RNA_def_property_update(prop, NC_SCENE | ND_RENDER_OPTIONS, NULL);
+
+	prop = RNA_def_property(srna, "use_max_b_frames", PROP_BOOLEAN, PROP_NONE);
+	RNA_def_property_boolean_sdna(prop, NULL, "flags", FFMPEG_USE_MAX_B_FRAMES);
+	RNA_def_property_clear_flag(prop, PROP_ANIMATABLE);
+	RNA_def_property_ui_text(prop, "Use max B-frames", "Set a maximum number of B-frames");
 	RNA_def_property_update(prop, NC_SCENE | ND_RENDER_OPTIONS, NULL);
 
 	prop = RNA_def_property(srna, "buffersize", PROP_INT, PROP_NONE);
@@ -5439,6 +5480,24 @@ static void rna_def_scene_ffmpeg_settings(BlenderRNA *brna)
 	RNA_def_property_ui_text(prop, "Mux Packet Size", "Mux packet size (byte)");
 	RNA_def_property_update(prop, NC_SCENE | ND_RENDER_OPTIONS, NULL);
 
+	prop = RNA_def_property(srna, "constant_rate_factor", PROP_ENUM, PROP_NONE);
+	RNA_def_property_enum_sdna(prop, NULL, "constant_rate_factor");
+	RNA_def_property_clear_flag(prop, PROP_ANIMATABLE);
+	RNA_def_property_enum_items(prop, ffmpeg_crf_items);
+	RNA_def_property_enum_default(prop, FFM_CRF_MEDIUM);
+	RNA_def_property_ui_text(prop, "Output quality",
+	                         "Constant Rate Factor (CRF); tradeoff between video quality and file size");
+	RNA_def_property_update(prop, NC_SCENE | ND_RENDER_OPTIONS, NULL);
+
+	prop = RNA_def_property(srna, "ffmpeg_preset", PROP_ENUM, PROP_NONE);
+	RNA_def_property_enum_bitflag_sdna(prop, NULL, "ffmpeg_preset");
+	RNA_def_property_clear_flag(prop, PROP_ANIMATABLE);
+	RNA_def_property_enum_items(prop, ffmpeg_preset_items);
+	RNA_def_property_enum_default(prop, FFM_PRESET_MEDIUM);
+	RNA_def_property_ui_text(prop, "Encoding speed",
+	                         "Tradeoff between encoding speed and compression ratio");
+	RNA_def_property_update(prop, NC_SCENE | ND_RENDER_OPTIONS, NULL);
+
 	prop = RNA_def_property(srna, "use_autosplit", PROP_BOOLEAN, PROP_NONE);
 	RNA_def_property_boolean_sdna(prop, NULL, "flags", FFMPEG_AUTOSPLIT_OUTPUT);
 	RNA_def_property_clear_flag(prop, PROP_ANIMATABLE);