[FFmpeg-devel] [PATCH] Parsing ALS object type in MPEG-4

[Alex Converse]

On Fri, Oct 9, 2009 at 10:30 AM, Thilo Borgmann
<thilo.borgmann at googlemail.com> wrote:
> Thilo Borgmann schrieb:
>> Alex Converse schrieb:
>>> On Fri, Sep 18, 2009 at 6:42 PM, Baptiste Coudurier
>>> <baptiste.coudurier at gmail.com> wrote:
>>>> Hi,
>>>>
>>>> On 09/18/2009 03:35 PM, Thilo Borgmann wrote:
>>>>> Alex Converse schrieb:
>>>>>> On Sun, Aug 23, 2009 at 3:51 PM, Thilo
>>>>>> Borgmann<thilo.borgmann at googlemail.com> ?wrote:
>>>>>>> Revision 6 attached (rev. 5 skipped...)
>>>>>>>
>>>>>>> [...]
>>>>>>>
>>>>>>> Index: libavcodec/mpeg4audio.h
>>>>>>> ===================================================================
>>>>>>> --- libavcodec/mpeg4audio.h ? ? (revision 19689)
>>>>>>> +++ libavcodec/mpeg4audio.h ? ? (working copy)
>>>>>>> @@ -36,6 +36,7 @@
>>>>>>> ? ? int ext_sampling_index;
>>>>>>> ? ? int ext_sample_rate;
>>>>>>> ? ? int ext_chan_config;
>>>>>>> + ? ?int channels;
>>>>>>> ?} MPEG4AudioConfig;
>>>>>>>
>>>>>>> ?extern const int ff_mpeg4audio_sample_rates[16];
>>>>>>> Index: libavformat/mov.c
>>>>>>> ===================================================================
>>>>>>> --- libavformat/mov.c ? (revision 19689)
>>>>>>> +++ libavformat/mov.c ? (working copy)
>>>>>>> @@ -434,9 +434,13 @@
>>>>>>> ? ? ? ? ? ? ? ? MPEG4AudioConfig cfg;
>>>>>>> ? ? ? ? ? ? ? ? ff_mpeg4audio_get_config(&cfg, st->codec->extradata,
>>>>>>> ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?st->codec->extradata_size);
>>>>>>> + ? ? ? ? ? ? ? ?if (cfg.chan_config) {
>>>>>>> ? ? ? ? ? ? ? ? if (cfg.chan_config> ?7)
>>>>>>> ? ? ? ? ? ? ? ? ? ? return -1;
>>>>>>> ? ? ? ? ? ? ? ? st->codec->channels =
>>>>>>> ff_mpeg4audio_channels[cfg.chan_config];
>>>>>>> + ? ? ? ? ? ? ? ?} else {
>>>>>>> + ? ? ? ? ? ? ? ? ? ?st->codec->channels = cfg.channels;
>>>>>>> + ? ? ? ? ? ? ? ?}
>>>>>>> ? ? ? ? ? ? ? ? if (cfg.object_type == 29&& ?cfg.sampling_index< ?3) //
>>>>>>> old mp3on4
>>>>>>> ? ? ? ? ? ? ? ? ? ? st->codec->sample_rate =
>>>>>>> ff_mpa_freq_tab[cfg.sampling_index];
>>>>>>> ? ? ? ? ? ? ? ? else
>>>>>> The rest of this seems OK but Rob and Baptiste are the maintainers here.
>>>> Maybe we should always set ->channels in mpeg4audio_get_config, that would
>>>> simplify the code everywhere else. What do you think ?
>>> In principle that seems fine as long as it doesn't break muxing or
>>> decoding files with (those awful) PCEs. In practice this probably
>>> means adding yet more PCE code to mpeg4audio.[ch] since it doesn't
>>> look like there is any way to adapt ff_copy_pce_data (mpeg4audio.c) or
>>> decode_pce (aac.c) to this purpose.
>>>
>>> I would also accept having this as an inevitable goal and leaving it
>>> on a todo list for a while. This whole multichannel business in MPEG 4
>>> audio was dreadfully thought out but there is nothing we can do about
>>> it now.
>>
>> So........ I should move these "st->codec->channels = ..." into
>> ff_mpeg4audio_get_config() ?
>
>
> ping

However you want to do it is fine as far as I'm concerned. I don't
want to make refactoring stuff in AAC a prereq for landing this.