[FFmpeg-devel] [PATCH 3/4] Implement dynamic memory allocation for MJPEG's picture

[Ronald S. Bultje]

Hi,

On Wed, Feb 16, 2011 at 5:02 PM, Anatoly Nenashev
<anatoly.nenashev at ovsoft.ru> wrote:
> On 17.02.2011 00:38, M?ns Rullg?rd wrote:
>>
>> Anatoly Nenashev<anatoly.nenashev at ovsoft.ru> ?writes:
>>
>>
>>>
>>> ?From 38608bf9c49c2ce2c7b3edbfb4d4641ca160a990 Mon Sep 17 00:00:00 2001
>>> From: anatoly<anatoly.nenashev at ovsoft.ru>
>>> Date: Tue, 15 Feb 2011 11:33:56 +0300
>>> Subject: [PATCH 3/4] Implement dynamic memory allocation for MJPEG's
>>> picture
>>>
>>> ---
>>> ?libavcodec/jpeglsdec.c | ? 18 +++++++++---------
>>> ?libavcodec/mjpegbdec.c | ? ?2 +-
>>> ?libavcodec/mjpegdec.c ?| ? 44
>>> +++++++++++++++++++++++++++-----------------
>>> ?libavcodec/mjpegdec.h ?| ? ?2 +-
>>> ?4 files changed, 38 insertions(+), 28 deletions(-)
>>>
>>
>> [...]
>>
>>
>>>
>>> diff --git a/libavcodec/mjpegdec.c b/libavcodec/mjpegdec.c
>>> index 9792616..2db6760 100644
>>> --- a/libavcodec/mjpegdec.c
>>> +++ b/libavcodec/mjpegdec.c
>>> @@ -81,6 +81,13 @@ av_cold int ff_mjpeg_decode_init(AVCodecContext
>>> *avctx)
>>> ?{
>>> ? ? ?MJpegDecodeContext *s = avctx->priv_data;
>>>
>>> + ? ?if (!s->picture_ptr) {
>>> + ? ? ? ?s->picture_ptr = av_mallocz(sizeof(AVFrame));
>>> + ? ? ? ?if (!s->picture_ptr)
>>> + ? ? ? ? ? ? ?return AVERROR(ENOMEM);
>>> + ? ? ? ?s->picture_ptr->reference = 0;
>>> + ? ?}
>>> +
>>> ? ? ?s->avctx = avctx;
>>> ? ? ?dsputil_init(&s->dsp, avctx);
>>> ? ? ?ff_init_scantable(s->dsp.idct_permutation,&s->scantable,
>>> ff_zigzag_direct);
>>>
>>
>> [...]
>>
>>
>>>
>>> diff --git a/libavcodec/mjpegdec.h b/libavcodec/mjpegdec.h
>>> index 9c78ab2..a1dee59 100644
>>> --- a/libavcodec/mjpegdec.h
>>> +++ b/libavcodec/mjpegdec.h
>>> @@ -80,7 +80,7 @@ typedef struct MJpegDecodeContext {
>>> ? ? ?int h_max, v_max; /* maximum h and v counts */
>>> ? ? ?int quant_index[4]; ? /* quant table index for each component */
>>> ? ? ?int last_dc[MAX_COMPONENTS]; /* last DEQUANTIZED dc (XXX: am I right
>>> to do that ?) */
>>> - ? ?AVFrame picture; /* picture structure */
>>> + ? ?AVFrame *picture_ptr; /* pointer to picture structure */
>>> ? ? ?int got_picture; ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?///< ?we found a SOF
>>> and picture is valid, too.
>>> ? ? ?int linesize[MAX_COMPONENTS]; ? ? ? ? ? ? ? ? ? ///< ?linesize<<
>>> ?interlaced
>>> ? ? ?int8_t *qscale_table;
>>> --
>>>
>>
>> Why don't you simply make an array: AVFrame picture[2]?
>
> Because in this case this isn't enough. I should also add "picture_index"
> field and implement switching between pictures. I don't think this must be
> done in this file.

For mxpeg, and that's why that's in another patch (4/4) and file.

But this is mjpeg.c. You remove picture and replace it with
picture_ptr, and then allocate picture_ptr. Why not leave picture, add
picture_ptr so no extra allocation is needed?

Ronald