[FFmpeg-devel] [PATCH] Add ATRAC3+ decoder

[Paul B Mahol]

On 10/14/13, Maxim Polijakowski <max_pole at gmx.de> wrote:
> Am 14.10.2013 22:09, schrieb Michael Niedermayer:
>> On Mon, Oct 14, 2013 at 08:52:04PM +0200, Maxim Polijakowski wrote:
>>>>> +    const uint8_t *buf  = avpkt->data;
>>>>> +    int buf_size        = avpkt->size;
>>>>> +    ATRAC3PContext *ctx = avctx->priv_data;
>>>>> +    AVFrame *frame      = data;
>>>>> +    int i, ret, ch_unit_id, ch_block = 0, out_ch_index = 0,
>>>>> channels_to_process;
>>>>> +    float **samples_p = (float **)frame->extended_data;
>>>>> +
>>>>> +    frame->nb_samples = ATRAC3P_FRAME_SAMPLES;
>>>>> +    if ((ret = ff_get_buffer(avctx, frame, 0)) < 0) {
>>>>> +        av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
>>>>> +        return ret;
>>>>> +    }
>>>>> +
>>>>> +    init_get_bits(&ctx->gb, buf, buf_size * 8);
>>>> if ((ret = init_get_bits8(&ctx->gb, avpkt->data, avpkt->size)) < 0)
>>>>      return ret;
>>> Done.
>>>
>>>> [...]
>>>>
>>>>> +
>>>>> +/**
>>>>> + *  @file
>>>>> + *  DSP functions for ATRAC3+ decoder.
>>>>> + */
>>>>> +
>>>>> +#include <math.h>
>>>>> +
>>>>> +#include "libavutil/float_dsp.h"
>>>>> +#include "avcodec.h"
>>>>> +#include "sinewin.h"
>>>>> +#include "fft.h"
>>>>> +#include "atrac3plus.h"
>>>>> +#include "atrac3plus_data.h"
>>>>> +
>>>>> +#define ATRAC3P_MDCT_SIZE (ATRAC3P_SUBBAND_SAMPLES * 2)
>>>>> +
>>>>> +static AVFloatDSPContext atrac3p_dsp;
>>>> This looks strange and is probably incorrect, it probably should be in
>>>> private context.
>>>>
>>> What is wrong with that?
>> Initialization uses a local per instance flag
>> (avctx->flags & CODEC_FLAG_BITEXACT)
>> thus if there are 2 instances, one with the flag set and one not set
>> a single global context could only be corrct for both if the flag
>> has no effect and would be unused
>> so something in this looks wrong, either it shouldt be global or there
>> should be no local flag passed to it.
>
> Will the following code:
>
> avpriv_float_dsp_init(&atrac3p_dsp, CODEC_FLAG_BITEXACT);
>
> work correctly for me?
>
> Unfortunately, the purpose of those avctx->flags is completely opaque to
> me...
>

avctx->flags & CODEC_FLAG_BITEXACT

is not same as

CODEC_FLAG_BITEXACT


> Best regards
> Maxim
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