IPlayer TV

General technical overview

Programme IDs

All programme episodes on BBC TV are assigned a programme ID (PID) made up of lower-case letter and numbers of around 8 characters. More information on the format of the PID's can be found at the BBC Programme Guide. For Instance for Torchwood, you can see which programmes are available on iPlayer.

In addition to this, it is possible for episodes in iPlayer to have several published "versions". Every episode of a programme should have at least one version - the "original". Other versions that exist are:

version_type_id	name
AudioDescribed	Audio description
Lengthened	Lengthened
OpenSubtitled	Open subtitles
Original	Original version
Other	Other
Shortened	Shortened
Signed	Sign language
WarningsHigher	Stronger content warnings
WarningsLower	Milder content warnings
WarningsNone	No content warnings

Retrieving programme meta-data

See IPlayer_Metadata

Subtitles

Subtitles are available on some iPlayer programmes. The subtitles are in W3C Timed-Text format. The S button on the Flash based iPlayer makes use of this file. The URL for a specific subtitle feed is determined by obtaining the 'version pid' for the programme. Retrieving programme media stream information as described above. It will have a stanza with something like:

<media kind="captions"
        type="application/ttaf+xml"   >
        <connection
                priority="10"
                kind="http"
                server="http://www.bbc.co.uk/iplayer/subtitles/"
                identifier="b0008dc8rstreaming89808204.xml"
                href="http://www.bbc.co.uk/iplayer/subtitles/b0008dc8rstreaming89808204.xml"
        />
</media>

The subtitle feed can be downloaded from the URL pointed to in the href field, e.g.: http://web.archive.org/web/20090912060117/http://www.bbc.co.uk/iplayer/subtitles/b0008dc8rstreaming89808204.xml

Scripts and programs

See Programs

Windows P2P Version

See Windows P2P

Flash / RTMP Version

See Flash iPlayer

iPhone Version

See IPhone H.264 version

Nintendo Wii Flash Version

See Nintendo Wii

Nokia N96 / RTSP Version

See Nokia H.264 version

Note about technical image quality

Please note: the technical image quality varies widely across the different versions of iPlayer output, particularly between the DRM-enabled version for Windows, and the iPhone version. Taking one program as an example, "House of Saddam" episode 1, broadcast on Wed 30th July 2008, the compression details are as follows (iphone and Windows DRM versions only were compared):

Comparison Table

Reception Method	Access Method	Video Codec	Video Resolution	Video Bitrate	Video Quality	Audio Codec	Audio Bitrate	OverallBitrate
Nokia N95 3G (n95_3g - iplayer_streaming_n95_3g)	RTSP streaming	H.264	176 x 96	80 kbps	Very Low	AAC	32 kbps	113 kbps
Mobile WMV DRM	HTTP download	WMV 9	320 x 176	??? kbps	Well Below VHS	WMA9.1	??? kbps	??? kbps
Nokia N95 Wifi (n95_wifi - iplayer_streaming_n95_wifi)	RTSP streaming	H.264	320 x 176	128 kbps	Well Below VHS	AAC	64 kbps	192 kbps
Flash (flashnormal - iplayer_broadband_streaming)	RTMP streaming	On2 VP6	512 x 288	372 kbps	Below VHS	MP3 44kHz CBR	128 kbps	500 kbps
Flash (flashstd - iplayer_streaming_h264_flv_lo)	RTMP streaming	H.264	640 x 360	352 kbps	Below VHS	AAC	128 kbps	480 kbps
Nintendo Wii Flash (flashlow - iplayer_streaming_flv7)	RTMP streaming	Sorenson Spark	512 x 288		Below VHS			820 kbps
iPhone (iphone - iplayer_streaming_http_mp4)	HTTP download	H.264	483 x 272	400 kbps	Below VHS	AAC	112 kbps	512 kbps
Windows WMV DRM	Kontiki p2p	WMV 9	672 x 544	475 kbps	VHS	WMA 9.1	128 kbps	608 kbps
Flash (flashhigh - iplayer_streaming_h264_flv)	RTMP streaming	H.264	640 x 360	704 kbps	Near VHS	AAC+	96 kbps	800 kbps
Flash (flashvhigh - iplayer_streaming_h264_flv_high)	RTMP streaming	H.264	832 x 468	1404 kbps	better than VHS	AAC+	96 kbps	1500 kbps
Flash (flashhd - iplayer_streaming_h264_flv_hd)	RTMP streaming	H.264	1280 x 720	3072 kbps	better than DVD	AAC	128 kbps	3200 kbps