[FFmpeg-devel] [PATCH v9] lavf: palettized QuickTime video in Matroska
Michael Niedermayer
michael at niedermayer.cc
Mon Dec 28 15:29:45 CET 2015
On Mon, Dec 28, 2015 at 12:07:38PM +0100, Nicolas George wrote:
> L'octidi 8 nivôse, an CCXXIV, Mats Peterson a écrit :
> > Michael, he's talking about the OLD patch that was never applied. My patch
> > has been written from scratch, more or less. I did borrowed some palette
> > loops from mov.c, but I have also attributed the previous authors at the top
> > of qtpalette.c properly.
>
> I must say, I find this hunk from 7973603:
>
> + if (matroska->has_palette) {
> + uint8_t *pal = av_packet_new_side_data(pkt, AV_PKT_DATA_PALETTE, AVPALETTE_SIZE);
> + if (!pal) {
> + av_log(matroska->ctx, AV_LOG_ERROR, "Cannot append palette to packet\n");
> + } else {
> + memcpy(pal, matroska->palette, AVPALETTE_SIZE);
> + }
> + matroska->has_palette = 0;
> + }
>
> looks quite similar to this hunk from
> https://trac.ffmpeg.org/attachment/ticket/5071/patchmkvmov.diff :
>
> + if (matroska->pal) {
> + uint8_t *pal = av_packet_new_side_data(pkt, AV_PKT_DATA_PALETTE, AVPALETTE_SIZE);
> + if (!pal) {
> + av_log(matroska->ctx, AV_LOG_ERROR, "Cannot append palette to packet\n");
> + } else {
> + memcpy(pal, matroska->pal, AVPALETTE_SIZE);
> + }
> + av_freep(&matroska->pal);
> + }
>
> Especially the use of if/else for error, and actually ignoring the error,
> instead of the most common (and more correct, but the rest of the code
> ignores error too) "if...return AVERROR(ENOMEM)".
for reference: (similar code prior to the patches)
HEAD~20:libavdevice/x11grab.c- pkt->pts = curtime;
HEAD~20:libavdevice/x11grab.c- if (s->palette_changed) {
HEAD~20:libavdevice/x11grab.c- uint8_t *pal = av_packet_new_side_data(pkt, AV_PKT_DATA_PALETTE,
HEAD~20:libavdevice/x11grab.c- AVPALETTE_SIZE);
HEAD~20:libavdevice/x11grab.c- if (!pal) {
HEAD~20:libavdevice/x11grab.c: av_log(s, AV_LOG_ERROR, "Cannot append palette to packet\n");
HEAD~20:libavdevice/x11grab.c- } else {
HEAD~20:libavdevice/x11grab.c- memcpy(pal, s->palette, AVPALETTE_SIZE);
HEAD~20:libavdevice/x11grab.c- s->palette_changed = 0;
HEAD~20:libavdevice/x11grab.c- }
HEAD~20:libavdevice/x11grab.c- }
--
HEAD~20:libavformat/asfdec_f.c- if (asf_st->pkt.data && asf_st->palette_changed) {
HEAD~20:libavformat/asfdec_f.c- uint8_t *pal;
HEAD~20:libavformat/asfdec_f.c- pal = av_packet_new_side_data(&asf_st->pkt, AV_PKT_DATA_PALETTE,
HEAD~20:libavformat/asfdec_f.c- AVPALETTE_SIZE);
HEAD~20:libavformat/asfdec_f.c- if (!pal) {
HEAD~20:libavformat/asfdec_f.c: av_log(s, AV_LOG_ERROR, "Cannot append palette to packet\n");
HEAD~20:libavformat/asfdec_f.c- } else {
HEAD~20:libavformat/asfdec_f.c- memcpy(pal, asf_st->palette, AVPALETTE_SIZE);
HEAD~20:libavformat/asfdec_f.c- asf_st->palette_changed = 0;
HEAD~20:libavformat/asfdec_f.c- }
HEAD~20:libavformat/asfdec_f.c- }
--
HEAD~20:libavformat/mov.c- if (sc->has_palette) {
HEAD~20:libavformat/mov.c- uint8_t *pal;
HEAD~20:libavformat/mov.c-
HEAD~20:libavformat/mov.c- pal = av_packet_new_side_data(pkt, AV_PKT_DATA_PALETTE, AVPALETTE_SIZE);
HEAD~20:libavformat/mov.c- if (!pal) {
HEAD~20:libavformat/mov.c: av_log(mov->fc, AV_LOG_ERROR, "Cannot append palette to packet\n");
HEAD~20:libavformat/mov.c- } else {
HEAD~20:libavformat/mov.c- memcpy(pal, sc->palette, AVPALETTE_SIZE);
HEAD~20:libavformat/mov.c- sc->has_palette = 0;
HEAD~20:libavformat/mov.c- }
HEAD~20:libavformat/mov.c- }
[...]
--
Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB
Dictatorship naturally arises out of democracy, and the most aggravated
form of tyranny and slavery out of the most extreme liberty. -- Plato
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