From: Lynne <dev@lynne.ee>
To: FFmpeg development discussions and patches <ffmpeg-devel@ffmpeg.org>
Subject: Re: [FFmpeg-devel] [RFC PATCH 1/3] aacdec: always skip the first 2048 samples if there's no side data
Date: Tue, 3 Oct 2023 06:09:13 +0200 (CEST)
Message-ID: <NfnhX6u--R-9@lynne.ee> (raw)
In-Reply-To: <CACXFHsTZw+Sn-ZRZy3hV2Ggk0793EY2_6q8HENLnEX30-CY4kQ@mail.gmail.com>
Sep 12, 2023, 23:25 by tfoucu@gmail.com:
> On Tue, Sep 12, 2023 at 9:25 AM Lynne <dev@lynne.ee> wrote:
>
>> Sep 12, 2023, 09:43 by andreas.rheinhardt@outlook.com:
>>
>> > Lynne:
>> >
>> >> For some reason, this was never set, which meant all **raw** AAC in ADTS
>> >> streams, except faac, had extra samples at the start.
>> >>
>> >> Despite this being a standard MDCT-based codec with a frame size of
>> 1024,
>> >> hence a delay of 1024 samples at the start, all major encoders,
>> excluding
>> >> faac and FFmpeg, use 2048 samples of padding.
>> >>
>> >> The FFmpeg encoder will be modified to also output 2048 samples of
>> padding
>> >> at the start, to make it in line with other encoders.
>> >>
>> >
>> > Does this also have actual advantages besides "being in line with other
>> > encoders"?
>> >
>>
>> Not really. I don't have an opinion on this. 1024 is the natural
>> delay of the codec, so maybe it would be best to leave it at that.
>>
>>
>> Note:
>>
> Not all encoders add 2048. Another version of the Fraunhofer encoder will
> add only 1600 samples
>
> and for HE-AAC of the same encoder will add 3200 samples.
> Should we not then have an option to set it ?
>
That sounds reasonable, I've resent the patch.
Do you think it's reasonable to go 2048 samples?
It does cut off the default AAC decoder, in case the FIL extension
has been stripped.
_______________________________________________
ffmpeg-devel mailing list
ffmpeg-devel@ffmpeg.org
https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
To unsubscribe, visit link above, or email
ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".
prev parent reply other threads:[~2023-10-03 4:09 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-09-12 6:10 Lynne
[not found] ` <Ne7-l4q--3-9@lynne.ee-Ne7-pA6----9>
2023-09-12 6:11 ` [FFmpeg-devel] [RFC PATCH 2/3] decode: allow decoders to override skip_samples Lynne
2023-09-12 6:14 ` [FFmpeg-devel] [RFC PATCH 3/3] aacdec: allow to skip sbr start-up delay Lynne
[not found] ` <Ne70gnX--3-9@lynne.ee-Ne70juu----9>
2023-09-12 6:15 ` Lynne
2023-09-12 7:10 ` [FFmpeg-devel] [RFC PATCH 1/3] aacdec: always skip the first 2048 samples if there's no side data Andreas Rheinhardt
2023-09-12 16:25 ` Lynne
2023-09-12 21:24 ` Thierry Foucu
2023-10-03 4:09 ` Lynne [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=NfnhX6u--R-9@lynne.ee \
--to=dev@lynne.ee \
--cc=ffmpeg-devel@ffmpeg.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Git Inbox Mirror of the ffmpeg-devel mailing list - see https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
This inbox may be cloned and mirrored by anyone:
git clone --mirror https://master.gitmailbox.com/ffmpegdev/0 ffmpegdev/git/0.git
# If you have public-inbox 1.1+ installed, you may
# initialize and index your mirror using the following commands:
public-inbox-init -V2 ffmpegdev ffmpegdev/ https://master.gitmailbox.com/ffmpegdev \
ffmpegdev@gitmailbox.com
public-inbox-index ffmpegdev
Example config snippet for mirrors.
AGPL code for this site: git clone https://public-inbox.org/public-inbox.git