mp4,mpeg_es: Decode iods box and MP4_IOD_Tag OD

Author: wader

format/mp4/boxes.go

@@ -730,6 +730,9 @@ func decodeBox(ctx *decodeContext, d *decode.D, typ string) {
 		d.FieldU8("version")
 		d.FieldU24("flags")
 		d.FieldFormat("descriptor", &vpxCCRGroup, nil)
+	case "iods":
+		d.FieldU32("version")
+		d.FieldFormat("descriptor", &mpegESGroup, nil)
 	case "esds":
 		d.FieldU32("version")
 		_, v := d.FieldFormat("descriptor", &mpegESGroup, nil)

format/mp4/testdata/stz2.fqtest

@@ -46,7 +46,16 @@ $ fq -d mp4 'dv' stz2.mp4
      |                                               |                |        [1]{}: box 0x88-0x9c.7 (21)
 0x080|                        00 00 00 15            |        ....    |          size: 21 0x88-0x8b.7 (4)
 0x080|                                    69 6f 64 73|            iods|          type: "iods" (Object Descriptor container box) 0x8c-0x8f.7 (4)
-0x090|00 00 00 00 10 07 00 4f ff ff fe ff ff         |.......O.....   |          data: raw bits 0x90-0x9c.7 (13)
+0x090|00 00 00 00                                    |....            |          version: 0 0x90-0x93.7 (4)
+     |00 01 02 03 04 05 06 07 08 09 0a 0b 0c 0d 0e 0f|0123456789abcdef|          descriptor{}: (mpeg_es) 0x94-0x9c.7 (9)
+0x090|            10                                 |    .           |            tag_id: "MP4_IOD_Tag" (16) 0x94-0x94.7 (1)
+0x090|               07                              |     .          |            length: 7 0x95-0x95.7 (1)
+0x090|                  00 4f                        |      .O        |            od_id: 79 0x96-0x97.7 (2)
+0x090|                        ff                     |        .       |            od_profile_level: 255 0x98-0x98.7 (1)
+0x090|                           ff                  |         .      |            scene_profile_level: 255 0x99-0x99.7 (1)
+0x090|                              fe               |          .     |            audio_profile_level: 254 0x9a-0x9a.7 (1)
+0x090|                                 ff            |           .    |            video_profile_level: 255 0x9b-0x9b.7 (1)
+0x090|                                    ff         |            .   |            graphics_profile_level: 255 0x9c-0x9c.7 (1)
      |                                               |                |        [2]{}: box 0x9d-0x27b.7 (479)
 0x090|                                       00 00 01|             ...|          size: 479 0x9d-0xa0.7 (4)
 0x0a0|df                                             |.               |

format/mpeg/mpeg_es.go

@@ -261,6 +261,17 @@ func odDecodeTag(d *decode.D, edc *esDecodeContext, _ int, fn func(d *decode.D))
 				}
 			}
 		},
+		// TODO: where is the spec?
+		// https://xhelmboyx.tripod.com/formats/mp4-layout.txt
+		// https://github.com/FFmpeg/FFmpeg/blob/master/libavformat/movenc.c mov_write_iods_tag
+		MP4_IOD_Tag: func(d *decode.D) {
+			d.FieldU16("od_id")
+			d.FieldU8("od_profile_level")
+			d.FieldU8("scene_profile_level")
+			d.FieldU8("audio_profile_level")
+			d.FieldU8("video_profile_level")
+			d.FieldU8("graphics_profile_level")
+		},
 	}
 
 	// TODO: expectedTagID