[FFmpeg-devel] [PATCH v5] lavc/rawdec: Use AV_PIX_FMT_PAL8 for 1-bit raw AVI video, and more

Mats Peterson matsp888 at yahoo.com
Mon Jan 25 01:28:17 CET 2016


On 01/25/2016 01:23 AM, Mats Peterson wrote:
> On 01/25/2016 01:14 AM, Michael Niedermayer wrote:
>> On Fri, Jan 22, 2016 at 03:44:30PM +0100, Mats Peterson wrote:
>>> You'll have to excuse me, Michael, but the changes I've made,
>>> including the line alignment changes, are dependent on each other,
>>> and not easy or very logical to split. Here's a new version that
>>> displays the Matrix video correctly.
>>>
>>> Mats
>>>
>>> --
>>> Mats Peterson
>>> http://matsp888.no-ip.org/~mats/
>>
>>>   raw.c    |    2 -
>>>   rawdec.c |   92
>>> +++++++++++++++++++++++++++++++++++++++++----------------------
>>>   2 files changed, 62 insertions(+), 32 deletions(-)
>>> 7e3ead59067fc542c5ad6c3231ab5783bad57c0b
>>> 0001-lavc-rawdec-Use-AV_PIX_FMT_PAL8-for-1-bit-raw-AVI-vi.patch
>>>  From 0f99c5bdcf39230556eef82fa849dd6342208539 Mon Sep 17 00:00:00 2001
>>> From: Mats Peterson <matsp888 at yahoo.com>
>>> Date: Fri, 22 Jan 2016 15:38:26 +0100
>>> Subject: [PATCH v5] lavc/rawdec: Use AV_PIX_FMT_PAL8 for 1-bit raw
>>> AVI video, and more
>>>
>>> The stuff about 1-bit video not necessarily being black & white in
>>> QuickTime goes for AVI as well. Being 1 bit per pixel only means that
>>> the data is bi-level. The two colors can be any color. Since many
>>> 1 bpp AVI files don't have a palette following the BITMAPINFOHEADER,
>>> I'm setting a "default" black & white palette in raw_init_decoder().
>>>
>>> Also, the line alignment for 4 bpp and 8 bpp depths generated warning
>>> messages. The line alignment is now 16 bytes for 1, 2, 4, and 8 bpp
>>> depth.
>>>
>>> Mats
>>>
>>> ---
>>>   libavcodec/raw.c    |    2 +-
>>>   libavcodec/rawdec.c |   92
>>> ++++++++++++++++++++++++++++++++++-----------------
>>>   2 files changed, 62 insertions(+), 32 deletions(-)
>>>
>>> diff --git a/libavcodec/raw.c b/libavcodec/raw.c
>>> index 3f2cc11..3979c5c 100644
>>> --- a/libavcodec/raw.c
>>> +++ b/libavcodec/raw.c
>>> @@ -242,7 +242,7 @@ unsigned int avcodec_pix_fmt_to_codec_tag(enum
>>> AVPixelFormat fmt)
>>>   }
>>>
>>>   const PixelFormatTag avpriv_pix_fmt_bps_avi[] = {
>>> -    { AV_PIX_FMT_MONOWHITE, 1 },
>>> +    { AV_PIX_FMT_PAL8,    1 },
>>>       { AV_PIX_FMT_PAL8,    2 },
>>>       { AV_PIX_FMT_PAL8,    4 },
>>>       { AV_PIX_FMT_PAL8,    8 },
>>> diff --git a/libavcodec/rawdec.c b/libavcodec/rawdec.c
>>> index cb0364c..9c4e69a 100644
>>> --- a/libavcodec/rawdec.c
>>> +++ b/libavcodec/rawdec.c
>>> @@ -41,7 +41,7 @@ typedef struct RawVideoContext {
>>>       AVBufferRef *palette;
>>>       int frame_size;  /* size of the frame in bytes */
>>>       int flip;
>>> -    int is_1_2_4_bpp; // 1 bpp raw in mov, and 2 or 4 bpp raw in
>>> avi/mov
>>> +    int is_1_2_4_8_bpp; // 1, 2, 4 and 8 bpp raw in avi/mov
>>>       int is_yuv2;
>>>       int is_lt_16bpp; // 16bpp pixfmt and bits_per_coded_sample < 16
>>>       int tff;
>>> @@ -94,8 +94,11 @@ static av_cold int raw_init_decoder(AVCodecContext
>>> *avctx)
>>>               return AVERROR(ENOMEM);
>>>           if (desc->flags & AV_PIX_FMT_FLAG_PSEUDOPAL)
>>>
>>> avpriv_set_systematic_pal2((uint32_t*)context->palette->data,
>>> avctx->pix_fmt);
>>> -        else
>>> +        else {
>>>               memset(context->palette->data, 0, AVPALETTE_SIZE);
>>> +            if (avctx->bits_per_coded_sample == 1)
>>> +                memset(context->palette->data, 0xff, 4);
>>> +        }
>>>       }
>>>
>>>       if ((avctx->extradata_size >= 9 &&
>>> @@ -153,19 +156,20 @@ static int raw_decode(AVCodecContext *avctx,
>>> void *data, int *got_frame,
>>>       RawVideoContext *context       = avctx->priv_data;
>>>       const uint8_t *buf             = avpkt->data;
>>>       int buf_size                   = avpkt->size;
>>> +    int avpkt_stride               = avpkt->size / avctx->height;
>>>       int linesize_align             = 4;
>>>       int res, len;
>>>       int need_copy;
>>>
>>>       AVFrame   *frame   = data;
>>>
>>> -    if ((avctx->bits_per_coded_sample == 4 ||
>>> avctx->bits_per_coded_sample == 2
>>> -            || avctx->bits_per_coded_sample == 1) &&
>>> +    if ((avctx->bits_per_coded_sample == 8 ||
>>> avctx->bits_per_coded_sample == 4
>>> +            || avctx->bits_per_coded_sample == 2 ||
>>> avctx->bits_per_coded_sample == 1) &&
>>>           avctx->pix_fmt == AV_PIX_FMT_PAL8 &&
>>>          (!avctx->codec_tag || avctx->codec_tag ==
>>> MKTAG('r','a','w',' '))) {
>>> -        context->is_1_2_4_bpp = 1;
>>> +        context->is_1_2_4_8_bpp = 1;
>>>           context->frame_size = av_image_get_buffer_size(avctx->pix_fmt,
>>> -
>>> FFALIGN(avctx->width, 32),
>>> +
>>> FFALIGN(avctx->width, 16),
>>>
>>> avctx->height, 1);
>>>       } else {
>>>           context->is_lt_16bpp = av_get_bits_per_pixel(desc) == 16 &&
>>> avctx->bits_per_coded_sample && avctx->bits_per_coded_sample < 16;
>>> @@ -175,7 +179,7 @@ static int raw_decode(AVCodecContext *avctx, void
>>> *data, int *got_frame,
>>>       if (context->frame_size < 0)
>>>           return context->frame_size;
>>>
>>> -    need_copy = !avpkt->buf || context->is_1_2_4_bpp ||
>>> context->is_yuv2 || context->is_lt_16bpp;
>>> +    need_copy = !avpkt->buf || context->is_1_2_4_8_bpp ||
>>> context->is_yuv2 || context->is_lt_16bpp;
>>>
>>>       frame->pict_type        = AV_PICTURE_TYPE_I;
>>>       frame->key_frame        = 1;
>>> @@ -202,39 +206,65 @@ static int raw_decode(AVCodecContext *avctx,
>>> void *data, int *got_frame,
>>>       if (!frame->buf[0])
>>>           return AVERROR(ENOMEM);
>>>
>>> -    // 1 bpp raw in mov, and 2 or 4 bpp raw in avi/mov
>>> -    if (context->is_1_2_4_bpp) {
>>> -        int i;
>>> +    // 1, 2, 4 and 8 bpp raw in avi/mov
>>> +    if (context->is_1_2_4_8_bpp) {
>>> +        int i, j, row_pix = 0;
>>>           uint8_t *dst = frame->buf[0]->data;
>>>           buf_size = context->frame_size - AVPALETTE_SIZE;
>>> -        if (avctx->bits_per_coded_sample == 4) {
>>> -            for (i = 0; 2 * i + 1 < buf_size && i<avpkt->size; i++) {
>>> -                dst[2 * i + 0] = buf[i] >> 4;
>>> -                dst[2 * i + 1] = buf[i] & 15;
>>> +        if (avctx->bits_per_coded_sample == 8) {
>>> +            for (i = 0, j = 0; j < buf_size && i<avpkt->size; i++,
>>> j++) {
>>> +                dst[j] = buf[i];
>>> +                row_pix++;
>>> +                if (row_pix == avctx->width) {
>>> +                    i += avpkt_stride - (i % avpkt_stride) - 1;
>>> +                    j += 16 - (j % 16) - 1;
>>> +                    row_pix = 0;
>>> +                }
>>> +            }
>>> +        } else if (avctx->bits_per_coded_sample == 4) {
>>> +            for (i = 0, j = 0; 2 * j + 1 < buf_size &&
>>> i<avpkt->size; i++, j++) {
>>> +                dst[2 * j + 0] = buf[i] >> 4;
>>> +                dst[2 * j + 1] = buf[i] & 15;
>>> +                row_pix += 2;
>>> +                if (row_pix >= avctx->width) {
>>> +                    i += avpkt_stride - (i % avpkt_stride) - 1;
>>> +                    j += 8 - (j % 8) - 1;
>>> +                    row_pix = 0;
>>> +                }
>>>               }
>>> -            linesize_align = 8;
>>
>> decreasing linesize_align below the SIMD register size is undesirable
>> as it could lead to unaligned accesses in subsequent code using
>> the frames which would cause speedloss
>>
>>
>
> I haven't decreased anything, rather increased it from previous 4 and
> 8-byte line alignments to 16 bytes. Or do you want me to use 32-byte
> alignment? That's a lot of overhead. And please read your mail.
>
> Mats
>
> _______________________________________________
> ffmpeg-devel mailing list
> ffmpeg-devel at ffmpeg.org
> http://ffmpeg.org/mailman/listinfo/ffmpeg-devel

Please note the the above line is *removing* the "linesize_align = 8*, 
not adding.

Mats

-- 
Mats Peterson
http://matsp888.no-ip.org/~mats/


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