[FFmpeg-devel] [PATCH] avcodec: add IMM4 decoder

[Paul B Mahol]

On 8/16/18, James Almer <jamrial at gmail.com> wrote:
> On 8/16/2018 8:00 AM, Paul B Mahol wrote:
>> Hi,
>>
>> another patch attached, please review.
>
>> +static int decode_frame(AVCodecContext *avctx, void *data,
>> +                        int *got_frame, AVPacket *avpkt)
>> +{
>> +    IMM4Context *s = avctx->priv_data;
>> +    GetBitContext *gb = &s->gb;
>> +    AVFrame *frame = data;
>> +    unsigned type;
>> +    int ret, scaled;
>> +
>> +    if (avpkt->size <= 32)
>> +        return AVERROR_INVALIDDATA;
>> +
>> +    av_fast_padded_malloc(&s->bitstream, &s->bitstream_size,
>> +                          FFALIGN(avpkt->size, 4));
>> +    if (!s->bitstream)
>> +        return AVERROR(ENOMEM);
>> +
>> +    s->bdsp.bswap_buf((uint32_t *)s->bitstream,
>> +                      (uint32_t *)avpkt->data,
>> +                      (avpkt->size + 3) >> 2);
>> +
>> +    if ((ret = init_get_bits8(gb, s->bitstream, FFALIGN(avpkt->size, 4)))
>> < 0)
>
> Split this in two, just to be safe.

Why?, not mandatory.

>
>> +        return ret;
>> +
>> +    avctx->pix_fmt = AV_PIX_FMT_YUV420P;
>> +    avctx->color_range = AVCOL_RANGE_JPEG;
>> +
>> +    scaled = avpkt->data[8];
>> +    if (scaled < 2) {
>> +        int width, height;
>> +        int mode = avpkt->data[10];
>> +
>> +        switch (mode) {
>> +        case 1:
>> +            width = 352;
>> +            height = 240;
>> +            break;
>> +        case 2:
>> +            width = 704;
>> +            height = 240;
>> +            break;
>> +        case 4:
>> +            width = 480;
>> +            height = 704;
>> +            break;
>> +        case 17:
>> +            width = 352;
>> +            height = 288;
>> +            break;
>> +        case 18:
>> +            width = 704;
>> +            height = 288;
>> +            break;
>> +        default:
>> +            width = 704;
>> +            height = 576;
>> +            break;
>> +        }
>> +
>> +        if (s->changed_size == 1 &&
>> +            (avctx->width != width || avctx->height != height)) {
>> +            av_log(avctx, AV_LOG_ERROR, "Frame size change is
>> unsupported.\n");
>> +            return AVERROR_INVALIDDATA;
>> +        }
>> +        avctx->width = width;
>> +        avctx->height = height;
>
> ff_set_dimensions()?

These are hardcoded values, always sane.