[MPlayer-users] demux_real: invalid chunksize! (0) with certain RealAudio / COOK codec streams

Niemeyer Matthias NIM at colenco.ch
Wed Mar 18 21:57:44 CET 2009

The actual version of mplayer (Build SVN-r28994-4.3.2) cannot handle certain Real-Audio streams using the COOK codec. Some days ago, Radio Ukraina


changed their streams from the SIPRO to the COOK codec and enhanced the bandwidth from 16k to 20k. Since then, I can here it with better quality from my hardware-internet radio (blik radio station) and also using RealPlayer GOLD 11, but mplayer fails. 

mplayer rtsp://real.nrcu.gov.ua:7553/encoder/ru1channel.rm

gives the message 

demux_real: invalid chunksize! (0)

The program keeps hanging until I stop it with Ctrl-C. The whole message output (sorry, it's compiled in German language) is:

Konnte Namen für AF_INET6 nicht auflösen: real.nrcu.gov.ua

Löse real.nrcu.gov.ua auf für AF_INET...

Verbinde mit Server real.nrcu.gov.ua[]:7553 ...

Cache-Größe auf 640 KByte gesetzt.

Fülle Zwischenpuffer: 18.75% (122880 Bytes) 

REAL-Dateiformat erkannt!

Stream description: Audio Stream

Stream mimetype: audio/x-pn-multirate-realaudio-live

[real] Audiostream gefunden, -aid 0

demux_real: invalid chunksize! (0)


MPlayer wurde durch Signal 2 im Modul demux_open unterbrochen.


MPlayer wurde durch Signal 2 im Modul enable_cache unterbrochen.

rtsp: read error.

realrtsp: rdt chunk not recognized: got 0x51

realrtsp: rdt chunk not recognized: got 0xf8

RM: Kein Audiostream gefunden. -> kein Ton.


name: Radio Ukraine The First Channel


Öffne Audiodecoder: [ffmpeg] FFmpeg/libavcodec audio decoders

AUDIO: 44100 Hz, 1 ch, s16le, 20.7 kbit/2.93% (ratio: 2584->88200)

Ausgewählter Audiocodec: [ffcook] afm: ffmpeg (FFmpeg COOK audio)


[AO OSS] audio_setup: Kann Audiogerät /dev/dsp nicht öffnen: Permission denied

ao_nas: init(): Can't open nas audio server -> nosound

DVB card number must be between 1 and 4

AO: [null] 44100Hz 1ch s16le (2 bytes per sample)

Video: kein Video

Starte Wiedergabe...

A: 0.0 (unknown) of 0.0 (unknown) ??,?% 0% 

Beenden... (Ende)

The same error already occured with Mplayer SVN-r28519-4.3.2 (Feb 10, 2009) and even with version 1.0rc2-4.2.1 (Windows XP from the year 2007). What is quite strange is that MPlayer 0.90rc4-3.3 (suse-linux, 2003) can handle the stream data without problems.

I can also dump the stream to file using the -dumpfile option of the actual mplayer, but I can play this recorded stream only with RealPlayer, not with mplayer.

It looks like a bug to me, and I'd be glad if you could fix it.

Kind regards


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