Thanks for the response >Could you point me to the paragraph in the rfc >where this is suggested? I seem to have missed >it...
Paragraph 4.2: "Both type 0 and type 1 JPEG require two quantization tables." >Please see AVCodecContext->intra_matrix (for luma) >and av_codec_set_chroma_intra_matrix(). This would allow me to set my own tables I presume? I'd prefer to let the encoder decide the tables, all I want is an option to tell it to use two. >Please remove this from emails sent to a public >email list. Apologies, this was auto-generated on the mail server, I'm seeing if webmail makes a difference, otherwise I'll revert to using my personal email account. Mike ________________________________________ From: Libav-user [[email protected]] On Behalf Of Carl Eugen Hoyos [[email protected]] Sent: 15 July 2015 17:28 To: [email protected] Subject: Re: [Libav-user] MJPEG quantization tables Michael Toon <michael.toon@...> writes: > I am using the encoder libs to encode MJPEG video > which I am packaging up to send via RTP. The > encoded bit stream that I generate only appears > to have a single quantization table defined, > however the RTP payload format specifies that if > using custom quantization tables there should be > two separate quantization tables for luma and > chroma. Could you point me to the paragraph in the rfc where this is suggested? I seem to have missed it... > Having separate tables seems to make sense to try > and gain most encoding efficiency, especially > since I need to transmit two tables regardless. > Is there a reason why the MJPEG codec only > generates a single table (I don't know.) > is there an option that I can to use separate > tables? Please see AVCodecContext->intra_matrix (for luma) and av_codec_set_chroma_intra_matrix(). > This message contains confidential information Please remove this from emails sent to a public email list. Carl Eugen _______________________________________________ Libav-user mailing list [email protected] http://ffmpeg.org/mailman/listinfo/libav-user ______________________________________________________________________ This email has been scanned by the Symantec Email Security.cloud service. For more information please visit http://www.symanteccloud.com ______________________________________________________________________ Digital Barriers e-Mail Confidentiality and Disclaimer This message contains confidential information and is intended only for the individual named. Please notify the sender immediately by e-mail if you have received this e-mail by mistake and delete this e-mail from your system. E-mail transmission cannot be guaranteed to be secure or error-free as information could be intercepted, corrupted, lost, destroyed, arrive late or incomplete, or contain viruses. The sender therefore does not accept liability for any errors or omissions in the contents of this message, which arise as a result of e-mail transmission. The recipient should check this email and any attachments for the presence of viruses. The company accepts no liability for any damage caused by any virus transmitted by this email. Digital Barriers plc is a company registered in England and Wales. Registered number: 7149547. Registered office: Cargo Works, 1-2 Hatfields, London SE1 9PG, United Kingdom. For further information about Digital Barriers, please visit http://www.digitalbarriers.com/. ______________________________________________________________________ This email has been scanned by the Symantec Email Security.cloud service. For more information please visit http://www.symanteccloud.com ______________________________________________________________________ _______________________________________________ Libav-user mailing list [email protected] http://ffmpeg.org/mailman/listinfo/libav-user
