Add support for grayscale images with arbitrary maxvals.
The image data is rescaled to the nearest pix_fmt it will fit in (gray8 or gray16). Conversion is done inside the codec in order to avoid the need for 14 (or 65534) new pix_fmt's. Originally committed as revision 8704 to svn://svn.ffmpeg.org/ffmpeg/trunk
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@ -26,6 +26,7 @@ typedef struct PNMContext {
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uint8_t *bytestream_start;
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uint8_t *bytestream_end;
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AVFrame picture;
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int maxval; ///< maximum value of a pixel
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} PNMContext;
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static inline int pnm_space(int c)
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@ -142,8 +143,12 @@ static int pnm_decode_header(AVCodecContext *avctx, PNMContext * const s){
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return -1;
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if (avctx->pix_fmt != PIX_FMT_MONOWHITE) {
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pnm_get(s, buf1, sizeof(buf1));
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if(atoi(buf1) == 65535 && avctx->pix_fmt == PIX_FMT_GRAY8)
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s->maxval = atoi(buf1);
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if(s->maxval >= 256 && avctx->pix_fmt == PIX_FMT_GRAY8) {
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avctx->pix_fmt = PIX_FMT_GRAY16BE;
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if (s->maxval != 65535)
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avctx->pix_fmt = PIX_FMT_GRAY16;
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}
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}
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/* more check if YUV420 */
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if (avctx->pix_fmt == PIX_FMT_YUV420P) {
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@ -165,7 +170,7 @@ static int pnm_decode_frame(AVCodecContext *avctx,
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PNMContext * const s = avctx->priv_data;
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AVFrame *picture = data;
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AVFrame * const p= (AVFrame*)&s->picture;
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int i, n, linesize, h;
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int i, n, linesize, h, upgrade = 0;
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unsigned char *ptr;
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s->bytestream_start=
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@ -194,9 +199,14 @@ static int pnm_decode_frame(AVCodecContext *avctx,
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goto do_read;
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case PIX_FMT_GRAY8:
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n = avctx->width;
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if (s->maxval < 255)
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upgrade = 1;
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goto do_read;
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case PIX_FMT_GRAY16BE:
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case PIX_FMT_GRAY16LE:
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n = avctx->width * 2;
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if (s->maxval < 65535)
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upgrade = 2;
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goto do_read;
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case PIX_FMT_MONOWHITE:
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case PIX_FMT_MONOBLACK:
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@ -207,7 +217,19 @@ static int pnm_decode_frame(AVCodecContext *avctx,
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if(s->bytestream + n*avctx->height > s->bytestream_end)
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return -1;
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for(i = 0; i < avctx->height; i++) {
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if (!upgrade)
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memcpy(ptr, s->bytestream, n);
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else if (upgrade == 1) {
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unsigned int j, f = (255*128 + s->maxval/2) / s->maxval;
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for (j=0; j<n; j++)
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ptr[j] = (s->bytestream[j] * f + 64) >> 7;
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} else if (upgrade == 2) {
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unsigned int j, v, f = (65535*32768 + s->maxval/2) / s->maxval;
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for (j=0; j<n/2; j++) {
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v = be2me_16(((uint16_t *)s->bytestream)[j]);
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((uint16_t *)ptr)[j] = (v * f + 16384) >> 15;
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}
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}
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s->bytestream += n;
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ptr += linesize;
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}
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