[FFmpeg-devel] [PATCH 2/3] lavf/avienc: Write palette after BITMAPINFOHEADER

Michael Niedermayer michael at niedermayer.cc
Fri Feb 19 17:52:45 CET 2016


On Fri, Feb 19, 2016 at 04:35:17PM +0100, Mats Peterson wrote:
> 
> -- 
> Mats Peterson
> http://matsp888.no-ip.org/~mats/

>  avienc.c |   31 +++++++++++++++++++++++++++----
>  1 file changed, 27 insertions(+), 4 deletions(-)
> 8d58e7c344ff8650d971483a80211a9eeb540d20  0002-lavf-avienc-Write-palette-after-BITMAPINFOHEADER.patch
> From 0294d37cd23f971376290be68dd681513740bb06 Mon Sep 17 00:00:00 2001
> From: Mats Peterson <matsp888 at yahoo.com>
> Date: Fri, 19 Feb 2016 16:23:17 +0100
> Subject: [PATCH 2/3] lavf/avienc: Write palette after BITMAPINFOHEADER
> 
> ---
>  libavformat/avienc.c |   31 +++++++++++++++++++++++++++----
>  1 file changed, 27 insertions(+), 4 deletions(-)
> 
> diff --git a/libavformat/avienc.c b/libavformat/avienc.c
> index 4e7bca4..3c357a2 100644
> --- a/libavformat/avienc.c
> +++ b/libavformat/avienc.c
> @@ -79,6 +79,8 @@ typedef struct AVIStream {
>      AVIIndex indexes;
>  } AVIStream;
>  
> +static int hdr_pal_done;

this must be in the context, AVIStream
non constant statics would break if there are 2 avi muxers


> +
>  static int avi_write_packet_internal(AVFormatContext *s, AVPacket *pkt);
>  
>  static inline AVIIentry *avi_get_ientry(const AVIIndex *idx, int ent_id)
> @@ -211,6 +213,9 @@ static int avi_write_header(AVFormatContext *s)
>              return AVERROR(ENOMEM);
>      }
>  
> +    /* Palette after BITMAPINFOHEADER in strf chunk */
> +    hdr_pal_done = 0;
> +
>      /* header list */
>      avi->riff_id = 0;
>      list1 = avi_start_new_riff(s, pb, "AVI ", "hdrl");
> @@ -359,6 +364,12 @@ static int avi_write_header(AVFormatContext *s)
>                      && enc->pix_fmt == AV_PIX_FMT_RGB555LE
>                      && enc->bits_per_coded_sample == 15)
>                      enc->bits_per_coded_sample = 16;
> +                /* Use private data for palette offset */
> +                if (enc->bits_per_coded_sample <= 8) {
> +                    enc->priv_data = av_malloc(sizeof(int64_t));
> +                    if (!enc->priv_data)
> +                        return AVERROR(ENOMEM);
> +                }
>                  ff_put_bmp_header(pb, enc, ff_codec_bmp_tags, 0, 0);
>                  pix_fmt = avpriv_find_pix_fmt(avpriv_pix_fmt_bps_avi,
>                                                enc->bits_per_coded_sample);
> @@ -673,16 +684,28 @@ static int avi_write_packet(AVFormatContext *s, AVPacket *pkt)
>          if (ret) {
>              if (ret == CONTAINS_PAL) {
>                  int pc_tag, i;
> +                int pal_size = 1 << enc->bits_per_coded_sample;
> +                if (!hdr_pal_done) {
> +                    int64_t cur_offset = avio_tell(pb);
> +                    int64_t *pal_offset = (int64_t *)enc->priv_data;
> +                    avio_seek(pb, *pal_offset, SEEK_SET);
> +                    for (i = 0; i < pal_size; i++) {
> +                        uint32_t v = AV_RL32(data + size - 4*pal_size + 4*i);
> +                        avio_wl32(pb, v & 0xffffff);
> +                    }
> +                    avio_seek(pb, cur_offset, SEEK_SET);
> +                    av_free(enc->priv_data);
> +                    hdr_pal_done++;
> +                }
>                  avi_stream2fourcc(tag, stream_index, enc->codec_type);
>                  tag[2] = 'p'; tag[3] = 'c';
> -
>                  pc_tag = ff_start_tag(pb, tag);
>                  avio_w8(pb, 0);
>                  avio_w8(pb, 0);
>                  avio_wl16(pb, 0); // reserved
> -                for (i = 0; i<256; i++) {
> +                for (i = 0; i < pal_size; i++) {

this mismatches the stored size above


> -                    uint32_t v = AV_RL32(data + size - 1024 + 4*i);
> +                    uint32_t v = AV_RL32(data + size - 4*pal_size + 4*i);

> -                    avio_wb32(pb, v<<8);
> +                    avio_wl32(pb, v & 0xffffff);

it looked correct when i tested this before the patch

[...]

-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

I do not agree with what you have to say, but I'll defend to the death your
right to say it. -- Voltaire
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