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Merged
merged 5 commits into from
Jan 9, 2020
Merged

mpd: support for Accessibility element in AdaptationSet #69

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5427950
return element name unrecognized in adaptation set
flavioribeiro Oct 31, 2019
b6bd25e
extend elements in adaptation set to cover accessibility elements
flavioribeiro Nov 1, 2019
abd1b79
Merge pull request #1 from zencoder/master
flavioribeiro Dec 19, 2019
b357898
testing: add tests for the Accessibility element
zsiec Jan 7, 2020
8356b3b
testing: assert accessibility value in test
zsiec Jan 7, 2020
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1 change: 1 addition & 0 deletions mpd/fixtures/hbbtv_profile.mpd
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Expand Up @@ -15,6 +15,7 @@
<Representation audioSamplingRate="44100" bandwidth="67095" codecs="mp4a.40.2" id="800">
<AudioChannelConfiguration schemeIdUri="urn:mpeg:dash:23003:3:audio_channel_configuration:2011" value="2"></AudioChannelConfiguration>
</Representation>
<Accessibility schemeIdUri="urn:tva:metadata:cs:AudioPurposeCS:2007" value="1"></Accessibility>
</AdaptationSet>
<AdaptationSet mimeType="video/mp4" startWithSAP="1" scanType="progressive" id="7357" segmentAlignment="true">
<ContentProtection schemeIdUri="urn:mpeg:dash:mp4protection:2011" xmlns:cenc="urn:mpeg:cenc:2013" cenc:default_KID="08e36702-8f33-436c-a5dd-60ffe5571e60" value="cenc"></ContentProtection>
Expand Down
1 change: 1 addition & 0 deletions mpd/fixtures/live_profile.mpd
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Expand Up @@ -13,6 +13,7 @@
<Role schemeIdUri="urn:mpeg:dash:role:2011" value="main"></Role>
<SegmentTemplate duration="1968" initialization="$RepresentationID$/audio/en/init.mp4" media="$RepresentationID$/audio/en/seg-$Number$.m4f" startNumber="0" timescale="1000"></SegmentTemplate>
<Representation audioSamplingRate="44100" bandwidth="67095" codecs="mp4a.40.2" id="800"></Representation>
<Accessibility schemeIdUri="urn:tva:metadata:cs:AudioPurposeCS:2007" value="1"></Accessibility>
</AdaptationSet>
<AdaptationSet mimeType="video/mp4" startWithSAP="1" scanType="progressive" id="7357" segmentAlignment="true">
<ContentProtection schemeIdUri="urn:mpeg:dash:mp4protection:2011" xmlns:cenc="urn:mpeg:cenc:2013" cenc:default_KID="08e36702-8f33-436c-a5dd-60ffe5571e60" value="cenc"></ContentProtection>
Expand Down
1 change: 1 addition & 0 deletions mpd/fixtures/live_profile_dynamic.mpd
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Expand Up @@ -13,6 +13,7 @@
<Role schemeIdUri="urn:mpeg:dash:role:2011" value="main"></Role>
<SegmentTemplate duration="1968" initialization="$RepresentationID$/audio/en/init.mp4" media="$RepresentationID$/audio/en/seg-$Number$.m4f" startNumber="0" timescale="1000"></SegmentTemplate>
<Representation audioSamplingRate="44100" bandwidth="67095" codecs="mp4a.40.2" id="800"></Representation>
<Accessibility schemeIdUri="urn:tva:metadata:cs:AudioPurposeCS:2007" value="1"></Accessibility>
</AdaptationSet>
<AdaptationSet mimeType="video/mp4" startWithSAP="1" scanType="progressive" id="7357" segmentAlignment="true">
<ContentProtection schemeIdUri="urn:mpeg:dash:mp4protection:2011" xmlns:cenc="urn:mpeg:cenc:2013" cenc:default_KID="08e36702-8f33-436c-a5dd-60ffe5571e60" value="cenc"></ContentProtection>
Expand Down
1 change: 1 addition & 0 deletions mpd/fixtures/ondemand_profile.mpd
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Expand Up @@ -16,6 +16,7 @@
<Initialization range="0-628"></Initialization>
</SegmentBase>
</Representation>
<Accessibility schemeIdUri="urn:tva:metadata:cs:AudioPurposeCS:2007" value="1"></Accessibility>
</AdaptationSet>
<AdaptationSet mimeType="video/mp4" startWithSAP="1" scanType="progressive" id="7357" segmentAlignment="true">
<ContentProtection schemeIdUri="urn:mpeg:dash:mp4protection:2011" xmlns:cenc="urn:mpeg:cenc:2013" cenc:default_KID="08e36702-8f33-436c-a5dd-60ffe5571e60" value="cenc"></ContentProtection>
Expand Down
119 changes: 84 additions & 35 deletions mpd/mpd.go
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Expand Up @@ -5,6 +5,7 @@ import (
"encoding/hex"
"encoding/xml"
"errors"
"fmt"
"strings"
"time"

Expand Down Expand Up @@ -33,6 +34,12 @@ const (
AUDIO_CHANNEL_CONFIGURATION_MPEG_DOLBY AudioChannelConfigurationScheme = "tag:dolby.com,2014:dash:audio_channel_configuration:2011"
)

// AccessibilityElementScheme is the scheme definition for an Accessibility element
type AccessibilityElementScheme string

// Accessibility descriptor values for Audio Description
const ACCESSIBILITY_ELEMENT_SCHEME_DESCRIPTIVE_AUDIO AccessibilityElementScheme = "urn:tva:metadata:cs:AudioPurposeCS:2007"

// Constants for some known MIME types, this is a limited list and others can be used.
const (
DASH_MIME_TYPE_VIDEO_MP4 string = "video/mp4"
Expand All @@ -50,6 +57,7 @@ var (
ErrSegmentTemplateLiveProfileOnly = errors.New("Segment template can only be used with Live Profile")
ErrSegmentTemplateNil = errors.New("Segment Template nil ")
ErrRepresentationNil = errors.New("Representation nil")
ErrAccessibilityNil = errors.New("Accessibility nil")
ErrBaseURLEmpty = errors.New("Base URL empty")
ErrSegmentBaseOnDemandProfileOnly = errors.New("Segment Base can only be used with On-Demand Profile")
ErrSegmentBaseNil = errors.New("Segment Base nil")
Expand Down Expand Up @@ -117,46 +125,48 @@ type CommonAttributesAndElements struct {

type AdaptationSet struct {
CommonAttributesAndElements
XMLName xml.Name `xml:"AdaptationSet"`
ID *string `xml:"id,attr"`
SegmentAlignment *bool `xml:"segmentAlignment,attr"`
Lang *string `xml:"lang,attr"`
Group *string `xml:"group,attr"`
PAR *string `xml:"par,attr"`
MinBandwidth *string `xml:"minBandwidth,attr"`
MaxBandwidth *string `xml:"maxBandwidth,attr"`
MinWidth *string `xml:"minWidth,attr"`
MaxWidth *string `xml:"maxWidth,attr"`
ContentType *string `xml:"contentType,attr"`
ContentProtection []ContentProtectioner `xml:"ContentProtection,omitempty"` // Common attribute, can be deprecated here
Roles []*Role `xml:"Role,omitempty"`
SegmentBase *SegmentBase `xml:"SegmentBase,omitempty"`
SegmentList *SegmentList `xml:"SegmentList,omitempty"`
SegmentTemplate *SegmentTemplate `xml:"SegmentTemplate,omitempty"` // Live Profile Only
Representations []*Representation `xml:"Representation,omitempty"`
XMLName xml.Name `xml:"AdaptationSet"`
ID *string `xml:"id,attr"`
SegmentAlignment *bool `xml:"segmentAlignment,attr"`
Lang *string `xml:"lang,attr"`
Group *string `xml:"group,attr"`
PAR *string `xml:"par,attr"`
MinBandwidth *string `xml:"minBandwidth,attr"`
MaxBandwidth *string `xml:"maxBandwidth,attr"`
MinWidth *string `xml:"minWidth,attr"`
MaxWidth *string `xml:"maxWidth,attr"`
ContentType *string `xml:"contentType,attr"`
ContentProtection []ContentProtectioner `xml:"ContentProtection,omitempty"` // Common attribute, can be deprecated here
Roles []*Role `xml:"Role,omitempty"`
SegmentBase *SegmentBase `xml:"SegmentBase,omitempty"`
SegmentList *SegmentList `xml:"SegmentList,omitempty"`
SegmentTemplate *SegmentTemplate `xml:"SegmentTemplate,omitempty"` // Live Profile Only
Representations []*Representation `xml:"Representation,omitempty"`
AccessibilityElems []*Accessibility `xml:"Accessibility,omitempty"`
}

func (as *AdaptationSet) UnmarshalXML(d *xml.Decoder, start xml.StartElement) error {

adaptationSet := struct {
CommonAttributesAndElements
XMLName xml.Name `xml:"AdaptationSet"`
ID *string `xml:"id,attr"`
SegmentAlignment *bool `xml:"segmentAlignment,attr"`
Lang *string `xml:"lang,attr"`
Group *string `xml:"group,attr"`
PAR *string `xml:"par,attr"`
MinBandwidth *string `xml:"minBandwidth,attr"`
MaxBandwidth *string `xml:"maxBandwidth,attr"`
MinWidth *string `xml:"minWidth,attr"`
MaxWidth *string `xml:"maxWidth,attr"`
ContentType *string `xml:"contentType,attr"`
ContentProtection []ContentProtectioner `xml:"ContentProtection,omitempty"` // Common attribute, can be deprecated here
Roles []*Role `xml:"Role,omitempty"`
SegmentBase *SegmentBase `xml:"SegmentBase,omitempty"`
SegmentList *SegmentList `xml:"SegmentList,omitempty"`
SegmentTemplate *SegmentTemplate `xml:"SegmentTemplate,omitempty"` // Live Profile Only
Representations []*Representation `xml:"Representation,omitempty"`
XMLName xml.Name `xml:"AdaptationSet"`
ID *string `xml:"id,attr"`
SegmentAlignment *bool `xml:"segmentAlignment,attr"`
Lang *string `xml:"lang,attr"`
Group *string `xml:"group,attr"`
PAR *string `xml:"par,attr"`
MinBandwidth *string `xml:"minBandwidth,attr"`
MaxBandwidth *string `xml:"maxBandwidth,attr"`
MinWidth *string `xml:"minWidth,attr"`
MaxWidth *string `xml:"maxWidth,attr"`
ContentType *string `xml:"contentType,attr"`
ContentProtection []ContentProtectioner `xml:"ContentProtection,omitempty"` // Common attribute, can be deprecated here
Roles []*Role `xml:"Role,omitempty"`
SegmentBase *SegmentBase `xml:"SegmentBase,omitempty"`
SegmentList *SegmentList `xml:"SegmentList,omitempty"`
SegmentTemplate *SegmentTemplate `xml:"SegmentTemplate,omitempty"` // Live Profile Only
Representations []*Representation `xml:"Representation,omitempty"`
AccessibilityElems []*Accessibility `xml:"Accessibility,omitempty"`
}{}

var (
Expand Down Expand Up @@ -240,8 +250,14 @@ func (as *AdaptationSet) UnmarshalXML(d *xml.Decoder, start xml.StartElement) er
return err
}
representations = append(representations, rp)
case "Accessibility":
ac := new(Accessibility)
err = d.DecodeElement(ac, &tt)
if err != nil {
return err
}
default:
return errors.New("Unrecognized element in AdaptationSet")
return fmt.Errorf("unrecognized element in AdaptationSet %q", tt.Name.Local)
}
case xml.EndElement:
if tt == start.End() {
Expand Down Expand Up @@ -435,6 +451,12 @@ type Representation struct {
SegmentTemplate *SegmentTemplate `xml:"SegmentTemplate,omitempty"`
}

type Accessibility struct {
AdaptationSet *AdaptationSet `xml:"-"`
SchemeIdUri *string `xml:"schemeIdUri,attr,omitempty"`
Value *string `xml:"value,attr,omitempty"`
}

type AudioChannelConfiguration struct {
SchemeIDURI *string `xml:"schemeIdUri,attr"`
// Value will be an int for non-Dolby Schemes, and a hexstring for Dolby Schemes, hence we make it a string
Expand Down Expand Up @@ -1019,6 +1041,16 @@ func (as *AdaptationSet) addRepresentation(r *Representation) error {
return nil
}

// Internal helper method for adding an Accessibility element to an AdaptationSet.
func (as *AdaptationSet) addAccessibility(a *Accessibility) error {
if a == nil {
return ErrAccessibilityNil
}
a.AdaptationSet = as
as.AccessibilityElems = append(as.AccessibilityElems, a)
return nil
}

// Adds a new Role to an AdaptationSet
// schemeIdUri - Scheme ID URI string (i.e. urn:mpeg:dash:role:2011)
// value - Value for this role, (i.e. caption, subtitle, main, alternate, supplementary, commentary, dub)
Expand All @@ -1032,6 +1064,23 @@ func (as *AdaptationSet) AddNewRole(schemeIDURI string, value string) (*Role, er
return r, nil
}

// AddNewAccessibilityElement adds a new accessibility element to an adaptation set
// schemeIdUri - Scheme ID URI for the Accessibility element (i.e. urn:tva:metadata:cs:AudioPurposeCS:2007)
// value - specified value based on scheme
func (as *AdaptationSet) AddNewAccessibilityElement(scheme AccessibilityElementScheme, val string) (*Accessibility, error) {
accessibility := &Accessibility{
SchemeIdUri: Strptr((string)(scheme)),
Value: Strptr(val),
}

err := as.addAccessibility(accessibility)
if err != nil {
return nil, err
}

return accessibility, nil
}

// Sets the BaseURL for a Representation.
// baseURL - Base URL as a string (i.e. 800k/output-audio-und.mp4)
func (r *Representation) SetNewBaseURL(baseURL string) error {
Expand Down
33 changes: 33 additions & 0 deletions mpd/mpd_read_write_test.go
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Expand Up @@ -180,6 +180,35 @@ func TestExampleAddNewPeriod(t *testing.T) {
testfixtures.CompareFixture(t, "fixtures/newperiod.mpd", xmlStr)
}

func TestAddNewAccessibilityElementWriteToString(t *testing.T) {
m := NewMPD(DASH_PROFILE_LIVE, VALID_MEDIA_PRESENTATION_DURATION, VALID_MIN_BUFFER_TIME)
audioAS, err := m.AddNewAdaptationSetAudioWithID("7357", DASH_MIME_TYPE_AUDIO_MP4, VALID_SEGMENT_ALIGNMENT,
VALID_START_WITH_SAP, VALID_LANG)
if err != nil {
t.Errorf("AddNewAccessibilityElement() error adding audio adaptation set: %v", err)
return
}

_, err = audioAS.AddNewAccessibilityElement(ACCESSIBILITY_ELEMENT_SCHEME_DESCRIPTIVE_AUDIO, "1")
if err != nil {
t.Errorf("AddNewAccessibilityElement() error adding accessibility element: %v", err)
return
}

xmlStr, err := m.WriteToString()
require.NoError(t, err)
expectedXML := `<?xml version="1.0" encoding="UTF-8"?>
<MPD xmlns="urn:mpeg:dash:schema:mpd:2011" profiles="urn:mpeg:dash:profile:isoff-live:2011" type="static" mediaPresentationDuration="PT6M16S" minBufferTime="PT1.97S">
<Period>
<AdaptationSet mimeType="audio/mp4" startWithSAP="1" id="7357" segmentAlignment="true" lang="en">
<Accessibility schemeIdUri="urn:tva:metadata:cs:AudioPurposeCS:2007" value="1"></Accessibility>
</AdaptationSet>
</Period>
</MPD>
`
require.EqualString(t, expectedXML, xmlStr)
}

func LiveProfile() *MPD {
m := NewMPD(DASH_PROFILE_LIVE, VALID_MEDIA_PRESENTATION_DURATION, VALID_MIN_BUFFER_TIME,
AttrAvailabilityStartTime(VALID_AVAILABILITY_START_TIME))
Expand All @@ -194,6 +223,7 @@ func LiveProfile() *MPD {

_, _ = audioAS.SetNewSegmentTemplate(1968, "$RepresentationID$/audio/en/init.mp4", "$RepresentationID$/audio/en/seg-$Number$.m4f", 0, 1000)
_, _ = audioAS.AddNewRepresentationAudio(44100, 67095, "mp4a.40.2", "800")
_, _ = audioAS.AddNewAccessibilityElement(ACCESSIBILITY_ELEMENT_SCHEME_DESCRIPTIVE_AUDIO, "1")

videoAS, _ := m.AddNewAdaptationSetVideoWithID("7357", DASH_MIME_TYPE_VIDEO_MP4, VALID_SCAN_TYPE, VALID_SEGMENT_ALIGNMENT, VALID_START_WITH_SAP)

Expand Down Expand Up @@ -250,6 +280,7 @@ func LiveProfileDynamic() *MPD {

_, _ = audioAS.SetNewSegmentTemplate(1968, "$RepresentationID$/audio/en/init.mp4", "$RepresentationID$/audio/en/seg-$Number$.m4f", 0, 1000)
_, _ = audioAS.AddNewRepresentationAudio(44100, 67095, "mp4a.40.2", "800")
_, _ = audioAS.AddNewAccessibilityElement(ACCESSIBILITY_ELEMENT_SCHEME_DESCRIPTIVE_AUDIO, "1")

videoAS, _ := m.AddNewAdaptationSetVideoWithID("7357", DASH_MIME_TYPE_VIDEO_MP4, VALID_SCAN_TYPE, VALID_SEGMENT_ALIGNMENT, VALID_START_WITH_SAP)

Expand Down Expand Up @@ -305,6 +336,7 @@ func HbbTVProfile() *MPD {
_, _ = audioAS.SetNewSegmentTemplate(1968, "$RepresentationID$/audio/en/init.mp4", "$RepresentationID$/audio/en/seg-$Number$.m4f", 0, 1000)
r, _ := audioAS.AddNewRepresentationAudio(44100, 67095, "mp4a.40.2", "800")
_, _ = r.AddNewAudioChannelConfiguration(AUDIO_CHANNEL_CONFIGURATION_MPEG_DASH, "2")
_, _ = audioAS.AddNewAccessibilityElement(ACCESSIBILITY_ELEMENT_SCHEME_DESCRIPTIVE_AUDIO, "1")

videoAS, _ := m.AddNewAdaptationSetVideoWithID("7357", DASH_MIME_TYPE_VIDEO_MP4, VALID_SCAN_TYPE, VALID_SEGMENT_ALIGNMENT, VALID_START_WITH_SAP)

Expand Down Expand Up @@ -353,6 +385,7 @@ func OnDemandProfile() *MPD {
_, _ = audioAS.AddNewContentProtectionRoot("08e367028f33436ca5dd60ffe5571e60")
_, _ = audioAS.AddNewContentProtectionSchemeWidevineWithPSSH(getValidWVHeaderBytes())
_, _ = audioAS.AddNewContentProtectionSchemePlayreadyWithPSSH(VALID_PLAYREADY_PRO)
_, _ = audioAS.AddNewAccessibilityElement(ACCESSIBILITY_ELEMENT_SCHEME_DESCRIPTIVE_AUDIO, "1")

audioRep, _ := audioAS.AddNewRepresentationAudio(44100, 128558, "mp4a.40.5", "800k/audio-und")
_ = audioRep.SetNewBaseURL("800k/output-audio-und.mp4")
Expand Down
27 changes: 27 additions & 0 deletions mpd/mpd_test.go
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Expand Up @@ -457,3 +457,30 @@ func getValidWVHeaderBytes() []byte {
}
return wvHeader
}

func TestAddNewAccessibilityElement(t *testing.T) {
m := NewMPD(DASH_PROFILE_LIVE, VALID_MEDIA_PRESENTATION_DURATION, VALID_MIN_BUFFER_TIME)
audioAS, err := m.AddNewAdaptationSetAudioWithID("7357", DASH_MIME_TYPE_AUDIO_MP4, VALID_SEGMENT_ALIGNMENT,
VALID_START_WITH_SAP, VALID_LANG)
if err != nil {
t.Errorf("AddNewAccessibilityElement() error adding audio adaptation set: %v", err)
return
}

_, err = audioAS.AddNewAccessibilityElement(ACCESSIBILITY_ELEMENT_SCHEME_DESCRIPTIVE_AUDIO, "1")
if err != nil {
t.Errorf("AddNewAccessibilityElement() error adding accessibility element: %v", err)
return
}

if g, e := len(audioAS.AccessibilityElems), 1; g != e {
t.Errorf("AddNewAccessibilityElement() wrong number of accessibility elements, got: %d, expected: %d",
g, e)
return
}

elem := audioAS.AccessibilityElems[0]

require.EqualStringPtr(t, Strptr((string)(ACCESSIBILITY_ELEMENT_SCHEME_DESCRIPTIVE_AUDIO)), elem.SchemeIdUri)
require.EqualStringPtr(t, Strptr("1"), elem.Value)
}